MII.LKPOKID.fi 



MIMOSA. 



Ml 



Ctriofora. Animals unknown ; celli poriform, round, close, irregu- 

 larly ilwtribiiU-il in concentric layer* ; polyparium polymorphous, 

 often globular or UmelUr. 



Thi genus was established by Goldfuss, but is curtailed by a stricter 

 definition by Da Blainville, to suit fossil* which appear in the Chalk of 

 liaeatricht and the Transition Rock* of Bamberg. Ex. (J. micropor*. 

 (Goldfuss, tab. 10, f. 4.) 



Clurytaora. Animali unknown ; cclU porifomi, very fine, with a 

 round opening, accumulated on the intervals of ridges, which anasto- 

 mose on the surface of the fixed irregularly ramose polyparium. 



It is a genus of Lamouronx. to which DC Blainville refers many of the 

 Crriopora of Goldfu**, which belong to the Oolitic Formations. Ex. 

 <.,,.iMta. (ljun.pl. 81, f. li.) 



Tilaia. AnimaU unknown ; the polyparium formed of tortuous 

 verrucow cylindrical branches ; cells small, accumulated in irregular 

 patches, which project above the general surface, and are separated by 

 smooth intervale. Ex. T. dittoita. (Lam., pi. 74, f. 5, 6.) From the 

 Oolite of Caen. 



Sfinopora. Animals unknown ; polyparium adherent by a concave 

 concentrically striated face below ; above reticulated, tuberculated, 

 and bearing between the tubercles poriform cells. Fossil from the 

 Chalk. Three species. Ex. S. mitra. (De Blain., pi. 70, f. 3.) 



Dittickopora. Animals unknown ; cells of two kinds ; some stelli- 

 form, scattered, superficial, shallow; the others poriform, deep, 

 unequal, forming three lateral rows on each side of the branches of 

 an arborescent polyparium these branches are compressed, obtuse, 

 subflexuous, and tubulose within. 



This Lamarckian genus contains the Miltepora riolacea of Liuuaeus. 

 (De. Blainv., pi. 55, f. 2.) 



IJeteropora. Animals unknown ; cells round, poriform, completely 

 immersed, of two sorts ; some, larger than the others, are regularly 

 dispersed on the whole surface of the polyparium, which is fixed, 

 lobed, or branched, and formed of superposed lamina}. 



It is a genus of De Blainville, formed to include certain Ctriopora of 

 Goldfuss which have two sorts of pores. Ex. H. eryptopora. (Gold- 

 fuse, tab. 10, f. 3.) 



Jlrtfropora eryptopora. 

 a, 6, two specimens ; r, porea magnified. 



Fossil from the Chalk of Maastricht 



Mr. Lonadale mentions one from the Silurian Rocks. (Murchlsou's 

 '.Silurian System.') 



I 3. Cells round, and more or less tubular and prominent. 



Ptututopora, Animals unknown ; cells rather prominent, pustulose 

 or mammilUted, distant, with round openings ; polypnrium formed 

 of superposed laminae, cylindrical, digitiform, or a little branched, 

 fixed. 



The few fostils which have these characters are separated from the 

 Ceriopora of Ooldfuss by De Blainvillo. They are from the Chalk 

 and Oolite. Ex. P. nadreporacea. (Goldfuss, tab. 10, f. 12.) 



//orncra. -Animals unknown ; cells with a circular opening, promi- 

 nent, detached, dispersed almost quincuncially on the inner face of the 

 branches of a fragile ramulose polyparium, which is fistulose and 

 furrowed on the non-polypiferous face. 



It i a genus of Lamourpux, formed from Rdepora of Lamarck. It 



includes several living species, from the seas of Europe and Australasia, 



and more fonilx, chiefly from the Tertiary Strata, but Mr. Lonadale 



< one from the Dudley Limestone. Ex.// fronJtculata (Lam., 



!!. 71, f. 7,8,9.) 



Jfonttra frondmlato. 

 m, natural i!/c ; , e, frsfnu-ati of the upper ind lowr sides, 



Idmonta. Animals unknown; cells prominent, sub-conical, distinct, 

 with a circular opening, arranged in half rings or short cross-lines, on 

 two-thirds of the circumference of the branches of the polyparium, 

 which is not porous, but slightly channelled on the uon-culluliferou* 

 face ; the branches an divergent and triquetral 



One living species belong* to this genus of Lamouroux, and several 

 fossils from the Oolite of Caen, and Chalk and Tertiaries of Muvtricht 

 and Paris. Qoldfuss has included two of them among Ktteponz. 

 Kx. /. triqvetra. (Lam., pL 79.) From the Oolite of Caen. 



Cricopora. Animals unknown; cells tubular, rather prominent, 

 with a circular opening, arranged in rings transversely or obliquely on 

 the surface of a fragile polyparium, which branches into cylindrical 

 parts obtuse at the extremity. 



This genus was named Spiropora by Lamouroux, but it is only rarely 

 that the cells take anything approaching to a spiral arrangement. The 

 coral is alveolar through its mass. Some of the moat characteristic 

 species are fossils from Caen. F. Faujtuii is from the Chalk of 

 Maastricht, and De Blaiuvillo joins to the group two recent species, 

 Seriatopora annulata and S. niula (Lamarck). Ehrenberg calls the 

 group Myriazoon, and Wiegumnn Truncularia. 



MILLER'S DOG. [SQUALID*.] 



MILLER'S-THUMB. [Conoi.1 



MILLET. [SORGHUM.] 



MILLSTONE-GRIT is the title of a remarkable group of strata 

 which belong to the Carboniferous System, and separate the Coal 

 Formation from the Mountain Limestone. It may be regarded as 

 one of the many instances of transition on a large scale, which reveal 

 to the geologist local changes of level and position of the ancient 

 hinds, whereby new currents were occasioned in the sea, and new 

 depositions produced in iti bed. Instead of the deposiU of mountain 

 limestone generated by processes almost purely marine, we have in 

 the .Millstone-Grit group evidence of streams from the interior of 

 elevated lands and periodical currents which spread pebbles, sand, and 

 clay, with land-plants, over surfaces where previously corals and shells 

 were accumulated in the quiet sea. The character of this group varies 

 according to a certain law of development in passing from the south 

 to the north of England. It is of little importance in the south-west 

 of England, South Wales, or any of the midland coal-fields ; but in 

 Derbyshire it acquire* great thickness, and appears in some of the 

 most striking scones of that romantic county. Here it is a series of 

 thick arenaceous rocks, alternating with shales and flagstones below 

 the coal and above the limestone. Perhaps no more remarkable 

 feature in English geology can be noticed than the bold crag* of 

 millstone-grit which are crossed as the traveller proceeds from the 

 coal of Sheffield to the limestone of Castleton. 



Farther to the north, between the deep limestone dales of Yorkshire, 

 the millstone-grit rocks appear on the summit of Ingleborotigb, Peny- 

 ghent, and Wharnside, mixed with shales, limestones, ironstones, and 

 beds of coal. At least three distinct bands of coarse pebbly millstone- 

 grit here occur, though not in one hill, and a similar character belongs 

 to the series in Durham and Northumberland. Through all the 

 extreme north of England indeed the millstone-grit group passes by its 

 coal, ironstone, 4c., to the coal formation above, and by its limestones 

 and peculiar shales to the mountain limestone below, by so easy a gra- 

 dation that the whole appears one vast series of associated deposits. 



The rock from which the group is named the Millstone-Grit, is a 

 very coarse-grained quartzoso sandstone, with layers of pebbles, often 

 defining the upper or under surfaces of beds, and sometime* (as near 

 Kvighley) containing remarkable masses of laminated mica, which is 

 not common in the substance of the stone. The most coarse and 

 quart zose parts of the stone have a vague resemblance to unmicaceoua 

 granites (as that of Ravenglass), and this is strengthened by the 

 occasional abundance of felspar, in large masse* crystallised within, 

 but fragmented or worn to a pebbly aspect externally. This discloses 

 probably the true history of the rock. It is a re-aggregated mass of 

 the disintegrated materials of granite ; and as almost every sandstone 

 of the coal district* is liable to assume locally the coarseness of grain 

 of the millstone-grit, and all appear to contain felspar grains and 

 fragments (often decomposed to porcelain clay), the importance of a 

 study of the Millstone-Grit becomes evident. The organic remains are 

 a mixture of those belonging to the Coal Formation (Plants), and 

 those of the subjacent Limestone (C'oncliifera, JUoUiuca). 



MILVUS. IFALCOHIDA] 



MIMOSA, a genus of Plants belonging to the natural order Lryu- 

 minotat. It has polygamous flower* ; petals 4 or 5, connected together 

 into a 4- or 5-cleft funnel-shaped corolla ; stamen* inserted in the base 

 of the corolla, or in the stipe of the ovary, equal in number to the 

 lobe* of the corolla, or double or triple that number ; legume cotn- 

 preuwd, flat, 1- or many-jointed; joints 1 -seeded; ribs permanent; 

 stipules petiolar ; leaves bipinuate, with one or more pairs of pinna;, 

 each pinna bearing 2 or many pairs of leaflet* ; flowers rose-coloured 

 or white, disposed in head*. The leave* are frequently sensible to 

 touch, as in the Sensitive Plant The species are very numerous. 



It. tentitiva, the Sensitive Plant, has prickly stem* and petioles ; 

 leaflet* ovate-acute, dotted, with adpressed pili beneath, but glabrous 

 above. It is a native of Brazil. The flowers are rose-coloured and 

 tetrandrous. The leaflet* are sensitive to touch, but not so much so 

 as the following specie*. 



