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PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. 



[Jan. 9, 



We descended Shaft No. 2, and examined the tunnel right and 

 left. Shaft No. 2 is in the Wenlock shales ; these are seen to 

 pass into the "Wenlock limestone (14 m. 406 yds.), which is thrown 

 down, and is horizontal. A glance at the section will explain the 

 extraordinary faulting of the rocks between Shaft No. 2 and the 

 Lower Ludlow rock and the point on the section where the strata 

 incline at an angle of 75°, which dip continues to the western exit of 

 the tunnel, throughout the Lower Ludlow shales, Aymestry rock, 

 Upper Ludlow shales, Downton sandstone, red and mottled marls, 

 grey shales and grits, and purple shales and sandstones, the tunnel 

 ending at the point where the red and grey Auchenaspis-beds pass 

 conformably into the underlying strata*. 



The following is the ascending order of the beds observed in the 

 section from 14 m. 957 yds. to 1463 yds.: — 1. Aymestry rock with 

 Pentamerus Knightii, &c. (10 feet). 2. Upper Ludlow rock with 

 CJionetes lata, &c. (140 feet). The Ludlow bone-bed seems to be 

 wanting here. 3. Downton bed, thin (9 feet), with Lingula. 4 to 8. 

 Red and mottled marls and thin sandstone (210 feet), with Lingula 

 and Pteraspis. 9. Grey shale and thin grit (8 feet), with Cepha- 

 laspis and Pterygotus. 10 and 11. Purple shales and thin sand- 

 stones (34 feet). 12. Grey marl passing into red and grey marl 

 and bluish-grey rock (20 feet), with Auchenaspis, Plectrodus, Cepha- 

 laspis, Onchus, Pterygotus Luclensis, Lingula, and a Lituite (*?). These 

 pass upwards conformably into a series of red marls, with yellowish 

 grey and pink sandstone containing Pteraspis and Oephalaspis, and 

 undoubtedly forming the base of the Cornstone-series of the Old 

 Red Sandstone. 



With the exception of colour, there is no possible means of draw- 

 ing any line of demarcation here between the Upper Silurian de- 

 posits and the lowest rocks of the Old Eed Sandstone. Fossils dimi- 

 nish in number in the Old Red, it is true ; but it is evident that this 

 is either owing to the change that occurred in the physical con- 

 ditions of the sea, or because the chemical condition of the deposits 

 was unfavourable to their preservation. As it is, we have a Lingula 

 common to the Downton beds and the Lower Old Red ; while Ce- 

 phalaspidian fishes, beginning in the Silurian (Lower LucUoav), con- 

 tinue upwards into the Old Red. 



The section from Malvern to Ledbury is most instructive and 

 most gratifying ; for we, who have followed in the wake of Murchi- 

 son, Strickland, Phillips, and the father of Malvern geology, the 

 present President of the Geological Society (Mr. Leonard Horner), 

 have learned upon how firm and scientific a basis the investigations 

 of these philosophers were founded, and how little we have been 

 enabled to add to the superstructure by later researches. 



* See the author's paper on the Ledbury Tuuuel, Quart. Journ. Greol. Soc. 

 vol. xvi. p. 193. 



