§6. 



GENERAL VIEW OF THE OOLITE AND LIAS. 



493 



Lower oolite 



of 

 Brora in Scot- 

 land. 



Shelly limestones — alternations of sandstones, 

 shales, and ironstone, with plants. 

 Ferruginous limestone, with carbonized wood, 

 leaves, shells, and cyprides. 

 Sandstone and shale, with tioo beds of coal. 



Lias 

 of 

 Dorsetshire, 

 Somersetshire, 

 Northampton- 

 shire, 

 and Yorkshire. 



1. Upper Lias shale, replete with remains of rep- 

 tiles, especially of Ichthyosauri and Plesio- 

 sauri : Crinoidea in profusion : Crustacea : be- 

 lemnites, ammonites, &c. ; nodular concretions 

 and beds of limestone. 



2. Lias marlstone — calcareous, sandy, and ferru- 



ginous strata, very rich in terebratulee and 

 other fossils ; wood, ferns, and cycadeous plants, 

 &c. I 



3. Lower Lias clay and shale — abounding in shells 

 — gryphea incurva, &c. — interlaminations of 

 sands and nodules of limestone. 



4. Lias rock; a series of laminated limestones, 



with partings of clay. 



This list, extensive as it appears, exhibits only the 

 principal deposits observable in the extensive series com- 

 prised in the Oolitic system. The difference observable 

 between the lower beds of the Oolites of the midland 

 counties, and those of Yorkshire and Scotland, in the 

 presence of accumulations of vegetable matter in the state 

 of coal, with the remains of terrestrial plants ; together 

 with the relics of insects, land-plants, and Mammalia, 

 in the Stonesfield slate, attest the existence of land, 

 and the action of rivers and currents. Our previous ob- 

 servations on the nature of oceanic deposits {ante, p. 57), will 

 have prepared the intelligent reader for such intercalations 

 of terrestrial detritus and organic remains in the beds of 

 the ancient seas. 



From the above table it is seen that the Inferior or lower 

 Oolite rests on the argillaceous beds termed Lias clays : 



