613 



ERMINE. 



ERRATIC BLOCKS. 



oil 



in others splintery. The structure granular and compact. Colour 

 light greenish-gray. Streak white, shining. Hardness 6'25 to 7'0. 

 Lustre feebly shining, or dull. Opaque. The specific gravity 3'0 to 3-1. 

 It is found near Erla in the Saxon Erzgebirge, forming a bed of 100 

 fathoms in thickness. Its analysis, by Gmelin, gives : 



Silica . . 



Alumina 



Lime 



Magnesia 



Soda 



Oxide of Iron 



Oxide of Manganese 



Water 



53-16 



14-03 



14-39 



5-20 



2-61 



7-14 



0-64 



0-60 



ERMINE. [MUSTELA.] 



ERNE. [FALCONID.R] 



ERNTO. [C'YrR.siD.E.] 



ERO'DIUM (from ipvSios, a heron), a genus of Plants belonging to 

 the natural order Geraniacece. It has 5 sepals, 5 petals, ] monadel- 

 phous stamens, 5 fertile and 5 sterile with glands at their base ; the 

 fruit beaked, separating into five 1-seetled capsules, each with a long 

 ultimately spirally-twisted awn, bearded internally. The species are 

 herbs or undershrubs, having variously-formed leaves, membranous 

 stipules, and many-flowered peduncles. The species of this genus, 

 like those of Geranium and Pelargonium, are numerous, upwards of 

 fifty having been described. 



. cifularitim, Hemlock-Leaved Heron's-Bill, has a procumbent 

 hairy stem, the peduncles many-flowered, the claws of the petals 

 ciliated, the perfect stamens dilated, not toothed below, glabrous, the 

 beak hairy, the leaves pinnate, the leaflets sessile, pinnatifid, cut. 

 The flowers are purplish or white. It is a native throughout the 

 whole of Europe, and is found in the north of Africa. It is abundant 

 on sandy soils and waste ground in Great Britain. There are several 

 well-marked varieties, some of which may be really species, as the 

 iiijiinellajii' 



E. motclta/um, Musky Heron's-Bill, has a procumbent hairy stem, 

 many-flowered peduncles, the claws of the petals not ciliated, the 

 perfect stamens toothed at the base, glabrous, the beak downy, the 

 leaves pinnate, the leaflets nearly sessile, ovate, unequally cut. It 

 is found in waste places in Great Britain, but is an unfrequent 

 plant. It is a larger plant than the preceding, nnd emits, when 

 handled, a strong musky odour. It is very generally diffused, and has 

 been found all over Europe, at the Cape of Good Hope, and in Peru. 



E. maritimum, Marine Heron's-Bill, has a prostrate slightly-hairy 

 stem, the peduncles 1-2-flowered, the petals very minute, the leaves 

 simple, ovate, cordate, stalked, lobed, and cremate. It is a rare plant, 

 bat a native of Great Britain, in sandy places near the sea. 



Most of the remaining species are natives of Europe; some are 

 found in the north of Africa, two or three in Asia, and the same 

 number in America ; but the mass of them are truly European. The 

 perennial species are ornamental, and will thrive well in any kind of 

 garden soil. They may be propagated by dividing the roots or by 

 seed. Many of the annual species are handsome plants, and may be 

 propagated by seed, which ripens in this country, and only requires 

 to be gown in the open border to spring in any kind of soil. 



EROPHILA. [DRABA.] 



EROTYLUS. [TETRAMERA.] 



ERPETOLOGY. [HERPETOLOOY.] 



' /-/" ''" tctttacHlatu*. 



E'RPETON, Lacdpede's name for a genus of Serpents, placed by 

 Cuvier next to Eryx. The name should be written Iferpeton. 



The genus is furnished with two soft prominences, covered with 

 scales on the muzzle. The head is protected by large plates ; those 

 beneath the belly are not large, and those beneath the tail scarcely 

 differ from the other scales. The tail however is very long and 

 pointed. Cuvier, who speaks of the priority of LaccSpede, who first 

 described the genus under the name of Erpeton, remarks that Merrem 

 has changed the name to Rhinopirus. 



ERRATIC BLOCKS are those weather-worn and more or less 

 rounded fragments of the harder rocks which are found very widely 

 scattered over the surface of the earth, and at great distances from 

 the places whence they are supposed to be derived. 



In size they vary from 10,000 cubic feet and upwards to a few 

 inches. M. Brongniart has proposed to designate the several sizes by 

 particular names, as gigantic, metric, cephallary, pugillary, &c. But 

 in England we generally confine the term Erratic Blocks to the larger 

 masses, calling those of middling size Boulders, and arranging the 

 smaller along with gravel : this is however too vague. The nature 

 of Erratic Blocks is not less various than their size. Every species 

 of rock seems to have contributed a portion of its substance towards 

 the mass, though the harder, being better capable of resisting the 

 disintegrating and corroding influence of atmospheric causes, are 

 found in the greatest abundance, such as quartz, petrosilex, green- 

 stone, granite, porphyry, syenite, gneiss, primitive and transition 

 limestone, dolomite, serpentine, siliceous pudding-stones, siliceous 

 sandstones, &c. 



The distribution and situation of these blocks are also very 

 different. Seldom isolated, they are generally found ift patches or 

 groups, as in the environs of Geneva, the plains of Westphalia, in 

 Sweden, c. ; or in long bands or trains, as in the north of Meek- 

 lenberg Strelitz, where they run in a direction west-north-west and 

 east-south-east ; or widely spread over considerable tracts, as between 

 Warsaw and Grodno, between St. Petersburg and Moscow, in East 

 Prussia, &c. Sometimes they cover horizontal plains, as in the north 

 of Germany ; sometimes they rest on the sloping sides of mountains, 

 as in the Alps and the Jura, and occasionally on the very tops of 

 lofty eminences, as on the summits of the calcareous mountains of 

 Rettwick, of Rsedaberg, and of Osmund, about 6000 feet above the 

 level of the sea. Sometimes they are seen in greatest abundance at 

 the bottom of valleys where they open into the plains, and in other 

 instances they are found collected in the largest quantity in the 

 high and narrow parts of the valleys, as is observed at Detmold and 

 east of Lemgo. At times they are so abundant as to be accumulated 

 into hills of a particular form, as is the case in Smaland, in Sweden; 

 and sometimes they form even mountains of considerable height, as 

 may be seen near Quedlie, in Norway; and what is remarkable, the 

 larger blocks are at the top, the others diminishing gradually towards 

 the bottom. 



Though generally superficially disposed, Erratic Blocks are however 

 in some places found imbedded in a fine sand which has nothing' in 

 common with their nature or origin, as in the plains of Westphalia. 

 Some blocks (and this may depend either on their own particular 

 nature, or the greater or less friction to which they have been 

 subjected, the length of time they have been exposed to atmo- 

 spheric influence, or the nature of the climate), have their angles 

 and edges as sharp as though they were just detached from 

 their native mountains, as is the case in the neighbourhood of 

 Groningen. 



When the Erratic Blocks are not at any great distance from the 

 spots whence they come, they may be easily traced up to their 

 origin. Thus those which are in the basin of the Rhine come from 

 the Orisons ; those of the valley of the Lake of Zurich and of the 

 Limmat have been detached from the mountains of Glaris ; those of 

 the basin of 'the Reuss come from the rocks at the source of this 

 river ; and those of the Aar and the Jura from the lofty mountains 

 in the canton of Berne. Even those which cover the widely extended 

 tract from Holland on the west, to St. Petersburg and Tver on the 

 east, are supposed by Von Buch, Hausmann; Brugmans, Alex. 

 Brongniart, &c. to be traceable to Scandinavia. .It is however 

 remarkable that, contrary to what is generally observed of trans- 

 ported debris, the blocks are frequently largest as they are farthest 

 removed from the place whence they came, diminishing gradually 

 in size as they approach the parent rock ; thus the blocks found 

 in Mecklenberg and Seeland, which are ascertained to be derived 

 from the Scandinavian peninsula, are larger than the blocks 

 of the same rocks in Scania and East Gothland, and they disap- 

 pear altogether close to the primordial mountains whence they were 

 derived. 



In certain places the blocks are almost exclusively of a particular 

 kind, while in others they vary greatly in their mineral character, 

 proving, together with the ascertained situation of the same 

 rocks in situ, that they must have been assembled from various 

 quarters. Thia is the case with the Erratic Blocks of Yorkshire, 

 and with those of Lithuania, for though the greater part, perhaps, of 

 those in the latter locality may be similar to the rocks ill Sweden 

 and Norway, there are many evidently derived from other places. 

 As for the direction in which the bands of Erratic Blocks seem to 



