50 WYNNE : GEOLOGY OF KHTCH. [pART I. 



limestones with sub-crystalline silieious varieties, thin bands of lumpy 



nodular conglomerate-like shale and layers of shelly limestone. One 



very peculiar rock is a coarse-grained, pebbly, glistening, golden oolite, 



the grains being coated with a thin film of lustrous brown haematite, that 



gives a resplendent appearance to the rock, which occasionally contains a 



few fossils. Ferruginous beds, except nodular ones, are more rare than 



higher up in the formation, though they sometimes 

 Ferruginous beds. . c , i i 



occur, and some ot them have a very peculiar, as it 



were, compressed angular concretionary form producing intricate concentric 



lines, the interspaces between which weathering away leave them in high 



relief. The component beds have a varying thickness, the shales of course 



being frequently finely laminated, and sometimes massed in bands, from 



100 feet to much greater thicknesses, almost entirely made up of them. 



Igneous rocks in many cases penetrate these lower Jurassics ; and in 



some have a strongly contemporaneous aspect, but 



as the unmistakeably intrusive varieties occur with 



or near them, the appearance of inter-stratification may be frequently 



due to intrusion between the aqueous beds. 



From a few somewhat indefinite zones, rather than from the whole 

 group generally, a large collection of marine fossils 

 has been obtained, including Tngonia, Astarte, 

 Gri/phma, Tereiratula, Ostrea, Cucullea, and numbers of other bivalves 

 with many Ammoniles, some of which are of great size; some Tleuroto- 

 maria, Chemnitzia, and a few more univalves ; remains of echiaoderms, 

 corals, fish teeth, reptilian bones, and quantities of Belemnites, — full 

 lists of which are given with the detailed descriptions in the following 

 pages. 



Many of the shales and more flaggy sandstones contain ill-preserved 

 but numerous plant impressions of grass-like forms, with some of more 

 woody nature and of considerable size ; while fragments of silicified fossil 

 timber are also to be met with. 

 ( 50 ) 



