98 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Jane 17, 



tend much to increase our knowledge of the physical conditions of 

 definite epochs in geology. In the present case the normal to these 

 lines, directed to the N.N.W., appears to the author to indicate the 

 existence of land in that quarter during the whole of the period now 

 under consideration, — land at no great distance, because of the pro- 

 portion of many of the plants, — the occurrence of Anodon and other 

 inhabitants of fresh or brackish water, — and the occasional" vertical 

 position of Equisetites. These latter facts, indeed, may require the 

 admission of the presence of low marshy land within the area in ques- 

 tion ; but the author is more impressed by the probability of high 

 and extensive land, which might yield to rivers, of some magnitude, 

 the enormous mass of quartz-sand and mixed ferruginous sediments 

 which abound between the truly marine limestones and subcalcareous 

 shelly bands. It seems necessary to suppose some old palaeozoic 

 land towards the north, not eminently granitic, but rather of the 

 argillaceous, arenaceous, and quartzose type, with intermixed trap- 

 rocks, such as the Lammermuir Range, which is now so abruptly 

 truncated on its eastern side. 



If an isochthonal line be drawn from near Thirsk to Robin Hood's 

 Bay, it will be found that on the north-western side the ironstone 

 band at the base of the Upper Lias is valuable for working — its 

 value growing greater to the north-west. 



Nearly on this line the Inferior Oolite receives its maximum dose 

 of iron, growing more and more sandy to the north-west, and losing 

 its thickness and character to the south-east. 



If a line be drawn from near Coxwold to Scarborough, parallel to 

 the preceding, it will nearly coincide with the north-western limit of 

 really oolitic character in the calcareous beds of Westow and Gris- 

 thorp, and with the south-eastern limit of the coal and freshwater 

 deposits of the district. For a limited breadth north-west of this 

 line, Belemnites Aalensis is found in the upper calcareous beds of the 

 Gristhorp series — a position much above what is usual for this shell, 

 — and it is associated at White Nab with Ammonites Blagdeni, 

 equally a species more common in the Inferior Oolite of the South 

 of England. 



The further development of this subject, the physical condition 

 and depth of the sea-bed, the alternate influence of sea- and fresh- 

 water in the same basin, and the relation of these rocks to those in 

 Lincolnshire and Oxfordshire, must be left for another communi- 

 cation. 



2. On the Oolite Rocks of Gloucestershire and North 

 Wilts. By James Buckman, F.G.S., F.L.S., F.S.A., Professor 

 of Natural History, Royal Agricultural College, Cirencester. 



[Plate VII.] 



Prefatory Remarks. — The object of the present paper is to 

 point out the general geological characteristics of the different mem- 

 bers of the Oolite rocks, as they occur in the Cotteswold Hills, 



