502 Mark Stirrup — Recent Changes of Level. 



limestones, as the land rose from the Zapata subsidence, although 

 it has subsequently been slightly depressed again. These canons 

 are all alike, and date only from the elevation following the mid- 

 Pleistocene deposits constituting the Zapata and gravels, and perhaps 

 marls, of about the same date as the Columbia formation of the 

 American coastal plain. ^ 



There are other basins in Cuba where subterranean passages carry 

 off the drainage, and those amongst the mountains are more striking 

 than the numerous lime-sinks of Florida. But the Yumuri basin 

 would have defied explanation had its outlet followed some other 

 course than across the faulted ridge (which had barred the ancient 

 drainage), and not exposed the dislocation. Some of the harbours 

 along the extended coast may be found to be of the same origin as 

 the Yumuri basin, and some of the valleys, such as that of Trinidad 

 on the southern side of the island, have been njore or less affected by 

 late faulting. 



VII. — A Eeply to Sib, H. Howorth's Paper on " Eecent Changes 



OF Level." 

 By Mabel Stirrup, F.G.S. 



IN a paper published in the Geological Magazine, September, 

 1894, Sir Henry Ho worth expatiates on recent changes of the 

 relative level of land and sea in support of his views on the 

 Mammoth age and his diluvial catastrophe, in which there seems 

 to me some very extraordinary confusion in the matter of geological 

 chronology and sequence of events. The first paragraph reads as 

 follows: — "In some recent papers published in the Geological 

 Magazine, I have endeavoured to show that at the close of the 

 Mammoth age there was a very considerable dislocation of the 

 Earth's crust, and that a consequence of it was the upheaval of 

 some of the highest masses of land on the earth, including the 

 massive mountains of Asia and the American Cordillera. I now 

 propose to show that (as is a priori probable) there was a con- 

 current collapse or sinking of the ground over large areas, which, 

 as in the corresponding upheaval, was very rapid, if not sudden " 

 (the italics are mine). The suggested relationship of these various 

 events and their alleged catastrophic character, induces me to again 

 enter this ever-expanding field of controversy. 



In support of his thesis Sir Henry first refers to the subsidences 

 which resulted in the separation of England from the Continent, 

 and consequent extinction of the Mammoth. 



Assuming that the course of things was as stated, when it is 

 further suggested that this event was contemporaneous with great 

 dislocation of the Earth's crust, resulting in stupendous upheavals of 

 mountain ranges in Asia and America, he attempts more than can 

 well be proved. Sir Henry proceeds, in the development of his argu- 

 ment, to the evidence offered by the remains of submerged foi'ests 

 which exist at various points around our coasts, and attributes their 



1 The Lafayette Formation, by W. J. McGee, 12th Report U.S. Geol. Survey. 



