102 



THE GEOLOGIST. 



are largest parallel to the strike, and are crossed at right angles by others, 

 cutting it up into immense square blocks, in their turn broken by smaller 

 fissures into smaller blocks; the surface stone is called the " clint " or 

 " clint cap," which affords a good study of the way molecular attraction, or 

 adhesion, has acted when the material forming the stone was in a viscid 

 state. There is another set of fissures on Asby Scar, containing copper 

 ore. In other formations of the same rock, small cracks have, by the pro- 

 colation of water, often become soldered up by the crystallization of car- 

 bonate of lime. On forcing these open again, large specks oflead ore are 

 sometimes found, a fact which, in part, may support the theory of lead be- 

 ing a deposit of crystallization of water. The characteristic fossils are 

 Producti, which are very numerous, but ill preserved, and often distorted 

 Euomphalus, Goniatites, and the black palatal bones of ganoid fishes. 



Some of the limestones, and all the sandstones, in this series of rocks 

 appear as though the material of which they are formed had settled one 

 stratum above another, without any upheaval of the bottom of the sea, 

 and are of one continued thickness throughout, to the outcrop ; while 

 others suggest the idea that the bottom has been gradually pushed up by 

 some upheaving power, or that the current bringing the sedimentary 

 matter failed to reach the outcrop, the stratum breaking off considerably 

 further back, and the next stratum further still. 



The next sandstone is very thin ; above it is a thin limestone of a hard 

 texture, in which Crinoids first became numerous ; its last surface afforded 

 a floor, on which have grown immense forests of Encrinites. Clay shale 

 of a dark colour is next superimposed by a grey purplish sandstone, con- 

 taining Stigmaria. In its uppermost beds on Harbyrn Rigg, immediately 

 below the limestone, are beds of Pectens, and other shells. The succeed- 

 ing limestone is very thin, and almost exclusively made up of broken coral ; 

 on two or three points, where it shows itself on high land, there is a 

 stratum of coral, — clear evidence of an ancient coral reef. ]S"ext in order 

 is a thin sandstone, generally overlaid by the next limestone : upon it 

 rests another stratum of sandstone, associated with which are definite traces 

 of another of the old coast-lines, exhibiting the variety of material forming 

 a beach. The sandstone contains immense quantities of Stigmaria ; at one 

 place where a large area is laid bare, these root-like plants run in all di- 

 rections, interlacing and overlapping each other in all directions, but in no 

 case affording proof of rising into stems of Sigillaria. The calcareous and 

 clayey deposits contain fragments of light shells and spines, of a pearly 

 lustre, with an occasional small Trilobite : these have evidently been 

 drifted, and quietly arranged in layers. JNext is a limestone of deep-sea 

 origin, the bluest in the series, and highl}* crystallized. It rises in thick 

 large blocks, with scarcely any cleavage or natural cracks : its fossils are 

 not numerous, but well preserved. Producti hare attained their largest 

 size ; Crinoids are numerous. Upon this limestone rests a yellow sand- 

 stone, twelve feel thick. — the base of a series of shales, sandstones, and 

 thin limestones, Lnterstratified with which are the Eeagill coal-seams. The 

 most important of these is immediately above the sandstone, with a clay 

 Bhale floor of two or three feet thick. The upper beds of the sandstone 

 and this shale are full of Stigmaria, then follows the coal-seam, from six to 

 twelve inches thick. We may consequently infer, that after this sand- 

 Btone, with its clayey surface, became partially dry land, a rank vegetation 

 of Sigillaria flourished, running their stigmariau roots deep into the clay 

 and sand, till a sinking of the land brought the sea once more over it, and 

 another deposit of olay Bhale six feet thick covered up the vegetable matter, 

 gradually to be compressed and mineralized. Next above the clay shale is 



