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THE EDINBURGH JOURNAL OF NATURAL HISTORY. 



the opening of the flower; and again, at the end of some time, takes the bend that 

 produces sleep. If, therefore, as cannot be duubted, it is the turgescence of the cel- 

 lular tissue of the nerves that produces the incurvation on vphich depends the wake 

 of the corolla or its expansion, it is to quite a different cause that we must refer the 

 incurvation to which is owing the sleep of the corolla or its closing ; for it cannot be 

 admitted that cellular tissue, immersed in water, is emptied. The experiment men- 

 tioned above proves that it is the fibrous tissue contained in each nerve of the corolla 

 that is the agent of the inward curvature, or that to which the sleep, or shutting of 

 the corolla, is due. We must, therefore, perceive, that in the nerves of the flower 

 of Mirabilis, the incurvation of waking, or that of which the concavity is directed 

 outwards, and which is owing to the turgescence of the cellular tissue, at first pre- 

 dominates over the incurvation of sleep, or tbat whose concavity is directed towards 

 the interior of the flower, and which is due to the action of the fibrous tissue ; and 

 that afterwards the incurvation of sleep, which depends upon this latter tissue, ulti- 

 mately proves victorious. The outward incurvation which the cellular tissue afl^ects 

 when the nerve is immersed in water, changes to inward curvation when the nerve 

 is immersed in syrup ; which proves that it is endosmosis that acts here. Now, 

 when the nerve, on being placed in water for some hours, has then taken the second 

 curvature, or that of sleep, it does not lose it when removed into syrup. It is not 

 then endosmosis that has occasioned this second incurvation, or that of sleep — (To 

 be continued. ) 



MISCELLANEOUS. 



DESCRIPTION OF THE FFvITH OF CROMARTY, AND REMARKS ON ESTUARIES, 

 The subject of Estuaries being one of great importance, not merely in a geological, 

 but also in an economical point of view, and more especially with relation to the sal- 

 mon fisheries, we have thought that an account of one of the most remarkable of 

 those of our Eastern coast might prove interesting to our readers. 



The Cromarty Frith is an Estuary or Inlet, extending from the northern coast of 

 the Moray Frith, in a slightly curved direction, to the town of Dingwall in the coun- 

 ty of Ross, having a length of about 21 miles, a breadth varying from 4 miles 

 in its widest part, to about 4000 feet at Cromarty and Invergordon Ferries ; and 

 faavmg an average breadth of a mile and three-fifths, so that its entire superficial 

 area is about 34 square miles. The whole extent of its southern coast is low, 

 the land rising from it gently to form the peninsula of the Black Isle, but hav- 

 ing a bank, in several places abrupt, and with an elevation of about 30 feet, ex- 

 cepting at its mouth, where it rises to a greater height. At its upper extremity the 

 shores are nearly flat. Along its northern side, for about a third of its length, they 

 are low, with a bank of small elevation, and not continuous. It is then succeeded 

 "by rather steep acclivities, forming the slopes of rounded hills of moderate height, 

 which are themselves the flanks of higher mountains placed farther back. Along 

 the middle third, the mountains recede to the distance of from one to three miles, 

 leaving a gradual slope, which becomes more or less level as it approaches the shores. 

 The ground along the remaining third is very low, but undulated; and the shores 

 are nearly fiat, excepting at the mouth of the Frith. There, on both sides, from 

 Cromarty Ferry to the coast line of the open sea. the banks gradually rise, then be- 

 come rocky and precipitous, and at length are formed of cliiFs from one to two hun- 

 dred feet in height, of a harder nature than those on any other part of its shores. 

 Here, on either side, is a rounded hill or ridge, several hundred feet high. On the 

 south side, the ridge continues some way along the coast of the Jloray Frith ; but 

 on the north side it soon terminates, by sloping gradually into a nearly level space, 

 extending obliquely from the eastern angle of the bay of Nigg to the sea coast at 

 Shandwick. This elevated ground may have been at one time continuous, as is per- 

 haps indicated by the exact similarity of the rocks on both sides of the very deep 

 channel formed by their disruption. If this were the case, the lake of fresh water, 

 formed by the Conon and other streams, in the basin marked by the steep banks along 

 the present Frith, would no doubt have emptied itself into the sea by the nearly 

 level and very low tract mentioned above as extending from the bay of Nigg to the 

 coast. 



A distinct channel, increasing in breadth and depth fiom the bridge over tlie Conon 

 to the Moray Frith, exists in the whole length of the basin ; while on either side are 

 shoals composed of mud and sand. The depth of this channel, in the lower parts of 

 the Frith, is unusually great, it being at Invergordon Ferry from 60 to 80 feet at 

 low water of spring tides, and at the entrance from 110 to 184. The most remark- 

 able shoals or sand banks are those extending along the bay of Nigg, and at low water 

 filling nearly half the breadth of the space from Invergordon Ferry to Cromarty Fer- 

 ry, which forms the widest part of the Frith, or that usually called Cromarty Bay. 

 Similar mud-flats occupy a great portion of the other bays on the Frith, and nearly 

 the whole of its upper part. The deposits which thus narrow the channel of the 

 waters, when the tide is out, are formed of sand intermixed with mud, and frequent- 

 ly have fragments of primitive rocks scattered over their surface, together with 

 cecayed shells of various kinds. Along the north shore of Cromarty Ferry is a de- 

 posit of pure quartzy sand, forming downs or sand hillocks, covered with sea-bent. 

 Many parts of the shoals in the upper portion of the Frith are composed chiefly of 

 gravel and stones, covered with sea-weeds, while others consist of sand and mud. 



The precipitous rocks along the coast of the Moray Frith, and a portion of the 

 narrow channel, extending from it to near the town of Cromarty, are formed of a 

 roek of a very different nature from those on the other parts of the shores of the Cro- 

 marty Frith, being of gneiss, and composed of quartz, felspar, mica, chlorite, and 

 hornblende, the quartz and felspar generally predominating. These clifi's and the 

 eminences bounded by them are commonly named the Sutors, although that appella- 

 tion is applied more particularly to certain fragments or detached masses at their base, 

 projecting from the water, and bearing a fanciful resemblance to cobblers at work. 

 The rocks here are composed of strata, generally thin, which are vertical, or inclined 

 fpom fifteen to twenty degrees on either side, that is, to the east and west, and often 

 extremely contorted. Their colour is generally red, owing to the predominance of 

 felspar in their composition. At their base are numerous fissures and small caves. 



some of which are inhabited by Rock Pigeons and Cormorants. Farther up the 

 channel the rocks become of a duller red, having a less crystalline texture, and are 

 chiefly composed of felspar ; their stratification is gradually obscured, and the mass 

 at length presents irregular fissures resembling those of an igneous deposit. This 

 rock is succeeded by vertical beds of red conglomerate and sandstone ; the former 

 composed of fragments of primitive rocks, chiefly quartz and gneiss ; the latter of 

 grains of quartz, cemented by argillaceous matter and oxide of iron, and intermixed 

 with scales of mica. Near the junction of the primitive and secondary rocks, im- 

 bedded in the sandstone, and about twelve yards distant from the edge of the con- 

 glomerate, is a bed of grey limestone, in thin parallel layers, from one to three or 

 four inches thick, with thinner layers of sandstone interposed. The rocks on the 

 south side are similar ; and the limestone bed, which is ten feet thick, runs nearly 

 north and south, and inclines about fifteen degrees to the west, is seen there also. 

 Beyond this the rocks are covered with sand on the north side, and with clay and 

 gravel on the south ; but where exposed by quarrying, are found to be sandstone of 

 the old red series, or of that kind named by some primitive sandstone, on account of 

 its resting upon and being formed of the detritres of primitive rocks. 



From Invergordon Ferry to Conon bridge the rocks continue of the same nature. 

 The sandstone is g,'nerally red, sometimes grey, whitish, or greenish, rather coarse- 

 grained, in some places firm, in others friable, composed of particles of quartz, mica, 

 and chloritic or argillaceous matter, very frequently having pebbles of quartz, gneiss, 

 and granitic rocks interspersed. The conglomerate is composed of pebbles of gneiss, 

 granite, quartz, hornblende-rock, mica slate, and fragments of other primitive rocks, 

 often little rounded, and cemented by argillaceous and arenaceous matter, generally 

 of a deep red colour. Towards Dingwall, on the north side of the Frith, are beds 

 of dark-grey or blackish rocks of the same nature. The strata are nearly horizontal, 

 or incline to the south-west at an angle varying from fifteen to twenty degrees, and, 

 along the shore-line of the southern side, where they sometimes present a fractured 

 face of twenty feet or more in height, have their seams of stratification parallel to 

 the water-line. The same rocks are seen in the bed of the Frith at its margin, but 

 rarely, being almost everywhere covered with sand or mud, and the shores near 

 high-water mark composed of pebbles of quartz, gneiss, and other primitive rocks. 



The soil of the surrounding country is a mixture of clay and sand, generally hav- 

 ing a large proportion of pebbles ; and the subsoil is of a similar nature, with frag-, 

 ments and blocks of primitive rocks. 



The vegetation along the shores is composed of the plants common to pasture lands 

 in all parts of Scotland, intermixed with those which are peculiar to maritime sta- 

 tions. There is very little natural wood, excepting on the north side, towards the 

 upper part. In the natural state, the vegetation of the southern side is heathy; but 

 the parts near the northern shores have either been cultivated or are covered with 

 pasture plants. Ammophila arundinacea and Triticu7n junceum, which are peculiar 

 to sand, cover the downs above mentioned near the mouth of the Frith. In short, 

 it may be generally observed, without specifying particular plants, that the vegetation 

 is of that mixed nature observed on the sea-coast, along estuaries, or by the mouths 

 of rivers to which the tides have access. 



The vegetation of the bed of the Frith is composed of marine Algae, which, it is 

 well known, are not peculiar to pure salt water, but occur also in the mixed salt and 

 fresh water of estuaries. In the Bay of Nigg, the extensive banks or flats are covered 

 to a great extent with Zostera marina, of which the fleshy, saccharine stems, and 

 long grassy leaves, afford abundant food to the vast flocks of Brent Geese, which 

 frequent the Frith in winter. This plant forms submersed meado%vs, and in winter 

 remains undecayed, although it assumes a duller green. It grows on sand and mud 

 banks and shoals, chiefly in sheltered places, sometimes in salt marshes or ditches 

 along the shore, but is not peculiar to estuaries, as it occurs abundantly on the coasts 

 of the Hebrides and Shetland Islands, in places where there is no intermixture of 

 fresh water. On the Nigg sands, attached to the stones and shells, are also con- 

 siderable quantities of algfp, of which may be mentioned Fucus serratiis, Fucus nodo- 

 s?fs, Fucus vesiculosus, Lamiiiaria saccharina, Laminaria digitata. and Scytosipko7i 

 filtnn. 



The quantity of algee in an estuary, or along the shores of the sea, is determined 

 by that of the rocky or stony ground, for these plants adhere only to a solid basis, 

 and do not grow out of mere sand and mud, although a very small point of support, 

 such as a dead shell or a pebble, is sufficient for them. Thus, in the mouth of the 

 Frith of Tay up to Broughty Castle, there are very few sea-weeds, because the bot- 

 tom and shores are sandy. On the sand and mud flats from thence, several miles 

 above Dundee, scarcely any are to be seen. But wherever rocks or stones occur, 

 either in the bed of the estuary or along its shores, they are found in profusion, and 

 the piers of the harbour of Dundee are densely covered with them nearly up to high- 

 water mark. In the Cromarty Frith these plants are in many places abundant, and 

 some of them are met with to a considerable distance above the mouth of the Conon. 

 On the flats of the Bay of Nigg they are very luxuriant, adhering in large tufts to 

 the stones; along the shores, above Invergordon Ferry, they attain a moderate size; 

 but towards the top of the Frith they gradually diminish, until, in the river itself, 

 they become dwarfish, and at length cease far below Conon Bridge. The predomi- 

 nant species above Invergordon are Fucus vesiculosvs, F. nodosus, and F. serratus, 

 which are the plants chiefly used in the manufacture of kelp; but besides these are 

 iovLTid F. canaliculatus, JLajninaria diffitata. Viva umhilicaliSi XJ. lactuca, and many 

 others. Although these and other Algje are peculiar to salt water, they are yet 

 frequently found in places where fresh water predominates for at least twelve out of 

 every twenty-four hours. — (Tb he continued.^ 



Edinburgh: Published for the Proprietor, at the Office, 16, Hanover Street. 

 London: Smith, Elder, and Co., Go, Cornhill. Glasgow and the "West of 

 Scotland: John Smith and Son; and John Macleod. Dublin: Georgji 

 Young. Paris : J. B. Balliere, Ruedel'Ecole de Medecine, No. 13 bis. 



THE EDINBURGH PRINTING COMFANT. 



