164 PROCEEDINGS OE THE GEOLOGICAL SOCIETY. [Jan. 8, 



for the opportunity of studying his collection. The following list 

 of fossils shows that the beds certainly belong to the Lower Oolites, 

 and probably to the division of the Inferior Oolite : — 



Pholadomya oblita, Lye. Sf Mor. 

 Myacites calceiformis, Phil., sp. 



, sp. 



Homomya, sp. 



Anatina, sp. 



Astarte rhomboidalis, Phil. 



Cyprina Loweana (?), Lye. Sf Mor. 



Cardium, sp. 



Cypricardia caudata, Lye. 



Lucina, sp. 



Area, sp. 



Tancredia angulata ? Phil., sp. 



axiniformis, Phil., §p. 



Myoeoncha, sp. 

 Modiola cuneata? Sow. 



imbricata, Sow. 



Lima duplicata? Sow. 



Pecten demissus ? Phil. 



Pteroperna, sp. 



Gervillia ? 



Ostrea Sowerbyi, Mor. $ Lye. 



Exogyra ? 



Rhynchonella varians ? Sow. 



, sp. 



Plant-remains. 

 Fucoid ? markings. 



The promontory of Burghead is formed by beds of coarse sand- 

 stones, often conglomeratic, faulted against the Heptiliferous Sand- 

 stone. The former, judging from their mineral characters, are not 

 improbably of the same age as the similarly situated beds of Stot- 

 field, but they have not yet, unfortunately, yielded any fossils. 



§ 7. TJie Middle Oolite. 



The Middle Oolite is very completely represented in Sutherland, 

 by several series of marine beds alternating with estuarine strata, 

 the whole attaining a great thickness. From the marine beds there 

 have been obtained some very interesting and beautiful series of 

 fossils, which enable us to identify several of those clearly marked 

 zones of life which have been distinguished by Dr. Oppel in Suabia*, 

 Professor Hebert in Francef, and Dr. Wright in England j. For a 

 thickness of more than 300 feet we have a succession of purely 

 marine strata, principally clays ; and this part of the series perhaps 

 more nearly resembles the equivalent beds in England than do any 

 other strata exposed on the east coast of Scotland. 



A. Zone of Ammonites calloviensis, Wright. — The lowest part of 

 this marine series is formed by a well-marked and everywhere 

 recognizable stratum, which we have already had occasion to mention 

 (the "roof-bed" of the main coal-seam). It is usually about 5 

 feet thick, though subject to considerable variation in this respect, 

 and consists of a hard more or less calcareous sandstone. In its 

 upper part it is crowded with marine shells, and sometimes passes 

 into a hard shelly limestone : in its lower part it is usually more 

 purely arenaceous, is crowded with plant-remains, and forms a con- 

 necting link between the marine strata above and the terrestrial 

 and estuarine beds below. The rock is throughout very ferru- 

 ginous, being generally of a dark greenish-grey colour when dug 

 under the clays, but weathering to a bright red tint upon the shore. 



* Oppel, ' Juraformation ' (1856-58) pp. 506, 615, &c. 

 t Hebert, ' Les Mers Anciennes,' etc. ^1857) p. 44. 



X Wrigbt, " On tbe Correlation of the Jurassic Rocks of the Cote-d'Or and 

 the Cotteswold Hills," Proc. Cotteswold Club, 1869. 



