344 J. F. BLAKE AND W. H. HUDLESTON ON 



top of the oolites of the Lower Limestones and the base of the 

 Middle Calcareous Grit*. 



It is probable that the shelly limestones and coarse fossiliferous 

 oolites which overlie the mass of the Lower Oolite and underlie the 

 Middle Calcareous Grit of this locality, are the true home of the origi- 

 nal A.perarmatus of Sowerby. This fossil was first described from the 

 " pisolite of Malton ;" but it certainly never occurs in the ordinary 

 Coralline oolite of that locality. The abundance of A. perarmatus in 

 beds lying at the top of the Lower Oolite would induce us to refer 

 the whole group palseontologically to the Lower Calcareous Grit. 



If we trace these beds along the sides of the Seven valley towards 

 Sinnington, we see them in great force flanking the hillside, and rest- 

 ing upon passage-beds of coarse gritty limestones, with Pectenjibrosas, 

 Gervillia avicidoides, and Lucina Beanii, which form the bed of the 

 river below Coptonbanks wood, and themselves rest on the " ball- 

 beds," as seen at the mill. Further south still, we see an old river- 

 cliff in which the top of this mass of Lower Limestones is exposed, 

 capped by a shell-bed which here, as elsewhere, seems the upper 

 limit, and may be probably on the horizon of the fossiliferous beds of 

 Whitethorn quarry. 



At the entrance to Sinnington gorge a magnificent section is ex- 

 posed, which will be more fully described in reference to higher 

 beds. At the base of this section 5 ft. of beds (E, fig. 15) represent the 

 shelly cap of the Lower Limestones. It is a coarse hackly oolite with 

 many pisolitic grains, and contains Ammonites cordatus, Chemniizia 

 heddingtonensis (fine), Exogyra nana, Anomia, sp., Pecten jibrosus, 

 Gervillia aviculoides, Lucina Beanii (v. c), Opis Phillipsi, Myacites, 

 sp., Trigoniaperlata. Above this lies the representative of the Middle 

 Grit (E, fig. 15), about 34 ft. in thickness, less arenaceous than in 

 Newtondale (Pickering), but with a fine development of Trigonia-he&s 

 towards the top. 



Between the valley of the Seven and Kirkdale the best sections 

 are obtained in the valleys of Hutton Beck and of the Dove f. On 

 or about this meridian the Lower Limestones seem to attain their 

 maximum, which, inclusive of the basement- or pa.ssage-beds, is not 

 much less than 150 feet. The base of the Lower Limestones is here 

 becoming cherty, and there are great accumulations of oolitic flint. 

 "West of Kirkdale this peculiarity increases greatly, and extends 

 downwards to the ball-bed series at the top of the Lower Calcareous 

 Grit proper. The Middle Calcareous Grit is well exposed in the bed 

 and on the flanks of the Kirkdale stream about opposite the church. 

 This is one of the best places for studying the junction with the 

 Lower Limestones. Its upper portion, containing the equivalent of 



* This proceeds upon the assumption that the oolite (b) of this quarry is 

 really the upper part of the oolite of the Cropton great lime -quarry ; should 

 that not be the case, the arguments founded on such a supposition, of course, 

 fall to the ground. 



t One of us had the good fortune lately to accompany Mr. Fox Strangways, 

 the Government Geological Surveyor, through these most interesting valleys, and 

 thus to profit by his great experience. 



