254 [ Proc - B.N.F.C., 



with marly layers, being the representatives of the Lower Keuper 

 — a division of the Trias only feebly represented in the district. 

 The variegated marls and clays which form the great mass of our 

 Keuper formation, succeed these beds, and are well seen in many 

 fine sections in the various stream courses, perhaps the best of 

 which is Springfield Glen, 



In the section given the Keuper marls immediately underlie 

 the Cretaceous beds, and the junction of the two formations may 

 be seen at Whiterock, and at the Windy Gap. At Hannahstown 

 Glen, a fault brings in the Lias and Rhaetic beds, but at the de. 

 tached position of the Cretaceous rocks seen at the waterfall in 

 Colin Glen, we find the marls of the Keuper occupying their 

 usual position at the base of the Greensand. 



Strata, belonging to the Rhsetic beds, and Lower Lias, rest 

 conformably on the Keuper marls. They are chiefly composed of 

 black shales, argillaceous limestones, and calcareous marls. I use 

 the word calcareous to distinguish these marls from those of the 

 Keuper, which contain little lime, and would be more properly 

 termed clays. These Liassic strata are very fossiliferous, and good 

 sections are seen along the river banks in Collin Glen. In the 

 Glen, at Hannahstown, these strata are very much indurated by a 

 large wedge-shaped projection of the basalt, which has curved the 

 strata round into Colin Glen, cut off portions of the Cretaceous 

 rocks, and broken the continuity of the escarpment, so that the 

 beds in Colin Glen are repeated several times as we ascend to the 

 waterfall. The Liassic strata are not continuous round the escarp- 

 ment, but seem to occupy a trough in the Keuper marls, and 

 occur under the same circumstances in many similar places, as at 

 Carr's Glen, at the Cave Hill. 



The lower basalt rests on the Chalk which it has hardened by 

 heat and pressure into the familiar, hard, white limestone, so pecu- 

 liar to our district. The surface of the Chalk upon which the 

 basalt rests is greatly worn and very uneven, some of the hollows 



