TORTWORTII TRAP INTRUSIVE. 



459 



and Woodford Green, (Horsely Quarry,) Michaelwood Chace, particularly on the bank 

 of the little river Avon, near Damory Mill ; on the left bank of that river, another line 

 extending from Daniel's Wood, by Crockley's, to Avening Green ; and, lastly, there are 

 two bands more or less parallel to each other in Charfield Green. From the apparent 

 conformability of one of these masses in Charfield Green to the associated strata, and 

 from the presence of organic remains in the trap itself, Mr. Weaver has founded his 

 best argument on the contemporaneous origin of the whole. When, however, narrowly 

 examined, I conceive that this evidence itself demonstrates irresistibly the posterior in- 

 trusion of the trap. The band in question, if followed from the open quarries in Char- 

 field Green, across the high road to Cullimore's Farm on the north, is seen to have a 

 very variable thickness, and so far from being a regular bed, is found to have a most 

 jagged and unequal surface. In one point, it is true, the igneous matter appears, though 

 for a very short distance, as if it dipped conformably with the associated strata of sand- 

 stone ; but this is soon ascertained to be nothing more than accident, for in pursuing 

 its course, the trap again breaks out, throwing off the stratified deposits both to the south- 

 west and west, and on reaching Cullimore's, the last point to the northward where this 

 band is visible, we find distinct proofs of its posterior intrusion. 



various small, acutely angular fragments, of 

 gritty impure limestone with shells, (such as at b,) of highly curved layers of shelly sandstone (c), 

 and semicircular bands of indurated shale (e), are twisted up in directions varying from vertical to 

 horizontal, and lost in the great mass of trap. In one spot, a coral (d) is seen to be completely 

 separated from the broken mass of shelly limestone (Z>), and included in the trappean paste. 



Besides their fragmentary and dislocated condition, these detached portions of sedi- 

 mentary strata are all more or less in altered conditions, being more compact and of 

 greater specific gravity than when found in natural beds divested of their trap associates. 

 This appears, therefore, to be one of those cases which is absolutely inexplicable upon 

 the supposition of contemporaneous origin, since these shelly strata must have been ori- 

 ginally deposited in regular successive layers, before they were subjected to the action 

 which has reduced them to their present shattered condition ; but if we simply view 

 this trap as the portion of an extensive dyke of igneous matter, ranging from north to 

 south, which in some parts has been intruded in a band between and nearly parallel to 

 the beds, and in others has burst through and fractured them, enveloping small frag- 

 ments of the strata in the mass of molten matter, we account naturally and simply for 



