1859.] WEIGHT INFERIOR OOLITE. 3 



our science, — the palaeontologist asserting that, when species are 

 critically studied, they are found to have a limited range in time — 

 the geologist arriving at an opposite conclusion. Palaeontologists 

 are thus said to draw hard lines in the study of the stratified rocks ; 

 whilst geologists attempt to shade off these lines, hy asserting that 

 species blend together in certain so-called passage-beds. 



These questions can only be settled by accurate observation and 

 a rigorous determination of the specific characters of the fossils im- 

 bedded in each superimposed stratum. When such an examination 

 of all the classes shall have been made, the comparative value 

 of the conclusions of the palaeontologist and geologist will be fairly 

 tested ; it will then, I venture to predict, become evident how 

 defective most of the lists of species in the infancy of our science 

 have been, and what an immense progress has been made by such 

 special critical studies. It is with the view of contributing my small 

 mite to this good cause, that I have drawn up with care lists of 

 fossils from the different zones of the Inferior Oolite for this memoir, 

 with the intention of proving that each of the subdivisions of that 

 formation contains certain species which are special to it, with others 

 that have a wider distribution. 



The thinning out of the zones in limited geographical areas, and 

 their absence in others, are facts which have been much overlooked, 

 and readily explain the presence or absence of intermediate beds in 

 certain localities, and the greater or less development of the same 

 at other places, constituting no deviation whatever from those laws 

 which regulate the distribution of species in time and space. 



§ II. TJie Cephalopoda-bed at Blue Wide, near Robin Hood's Bay, 

 Yorkshire. — In excursions made, in the summers of 1858 and 1859, 

 to Stainton-dalc Cliffs and the Peak, I had the satisfaction of finding 

 the true equivalent of the Cephalopoda-bed and sands at Blue Wick, 

 near Robin Hood's Pay, beneath a rock which I consider the base- 

 ment-bed of the Dogger, or Inferior Oolite — a- yellowish sandstone, 

 containing several scams of small round pebbles, which lie near the 

 bottom. The pebbly conglomerates arc about four inches in thick- 

 ness, and recur at intervals. The sandstone contains fragments of 

 Belemnites, Cerithium, and Monotis nitescens, Simpson. The bed is 

 about five feet, ami rests on No. I. n band of dark friable shale, 

 resting on a hard ironstone-band, full of fossils. This bed is very 

 micaceous in parts; and many of its Bhells are stained with per- 

 oxide of iron. I found clusters of Terebratula trilineata, Young 

 & Bird, in the sandstone, with Belt mnites compressus, Vbltz, B. 

 irregularis, Schloth., Trigonia I&cvmsayii, Wright, and Ehynchonella 

 cynocephala, Rich. The same species occur in a ferruginous Beam 

 of sandstone at Glaizedale. This bed is about eighteen inches thick, 

 ami rests on No. 2, '/'/" YeXUm Sandstone, which is well exposed at 

 Ulne Wick. It consists of irregular layers ofsofl yellow sandstone, 

 onequallj indurated: Borne portions weather oul and leave hollows 

 in the cliff; others are fine-grained, yellowish, highly micaceous, 

 thick-bedded, and variously jointed. The upper part of this roch is 



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