On Shells and Corals in a Conglomerate at Malvern. 289 



anticlinal and synclinal curvatures which on the western flank 

 of the Malverns affect equally the Silurian and old red forma- 

 tions, and then survey the comparatively horizontal and un- 

 moved strata of new red marls and sandstones, which on the 

 east and south touch indiscriminately the sienites, Caradoc 

 sandstones, Wenlock limestone, and old red sandstone, with- 

 out being satisfied that the great upward movement of the 

 Malvern rocks happened in the interval between the old and 

 the new red sandstones. 



But in what state were these plutonic masses raised ? as 

 fused and liquid matter, or solidified rock? To determine this 

 question, the observed positions of the strata which adjoin the 

 trap range are important, but their condition and contents are 

 still more essential. My first expectation, on looking gene- 

 rally at the narrow continuous range of the Malverns, was, 

 that here might be found an example of a gigantic sinuous 

 mass, emitted in a liquid state along a portion of that great 

 irregular fracture which is the western boundary of the new 

 red sandstone, from the Severn to the Dee. The complicated 

 nature of the trap, its innumerable vein-like segregations, its 

 included gneissic beds, gave an additional interest to the ex- 

 amination of the appearances at and near the junction of the 

 trap with the exterior stratified masses. 



In aid of this inquiry I fortunately discovered two re- 

 markable localities where Silurian strata of determinate age 

 were in contact with the trap masses; one exposed in the 

 deep cutting at the Wych, the other on the depressed sum- 

 mit of drainage between the Hereford beacon and Swin- 

 yard hill. Besides these are several examples of the sedi- 

 mentary aggregates of the lower Silurian strata in juxtaposi- 

 tion or actual contact with the trap rocks of the high Malvern 

 ridge; with a detached series of low insulated ridges and 

 bosses of trap on the western side near the southern extre- 

 mity of the chain ; and with some low mounds described by 

 Mr. Murchison at the northern extremity. 



The appearances connected with the low points at the 

 northern end, and with a part of the ridge near the southern 

 extremity, have been considered to indicate metamorphism in 

 stratified rocks by heat*; and the phsenomena associated 

 with the detached bosses and hillocks on the western side 

 of the chain, may be believed to indicate irruption of trap 

 amongst the lowest of the Silurian strata ; but generally along 

 the chain itself, and especially in all the northern parts of it, 

 there appears no evidence that the adjacent exterior strata 

 have been invaded by liquid irruptive rock. 



* Murchison's Silurian System, p. 417 etaeq. 



Phil. Mag. S. 3. Vol. 21 . No. 1 38. Oct. 184-2. U 



