570 Obituary— William Topley, F.R.8., F.G.S. 



estimate — the maximum effect, leaving out of account internal 

 friction, would be equal to raising a column of rock 1000 feet 

 above the normal of the Earth's surface ; but, when we come to 

 consider a local contraction of the crust, we have an exceedingly- 

 complex problem to deal with. Each section of the spherical shell, 

 such as we have assumed, would initially possess tensile strength 

 sufficient to put the same pressure per square inch upon the interior 

 of the sphere that the whole shell would ; but, as the area became 

 flattened by contraction, its power of compression would become 

 proportionally less. Taking this into consideration, together with 

 internal friction, in small areas the elevatory effect by transference 

 of material would become infinitesimal. 



If this reasoning be true, and I believe it to be so, Mountain- 

 Making by Tension is an impossibility. It will not account for 

 either the shape, height, bulk, or linear direction of Mountain 

 Ranges as we know them, much less the compression and folding 

 most of them have undergone. We are thus thrown back upon 

 some theory of compression would we account for mountain- 

 structure as seen in Nature. 



Before concluding, I woUld point out that, in addition to these 

 quantitative deficiencies, Mr. Vaughan's theory seems to involve a 

 mechanical contradiction. If the tensile strength of the contracting 

 crust were great enough to do the required work, a strong enough 

 anchorage would be needed at the boundaries ; whereas by the 

 hypothesis this is the weak part, otherwise it could not be elevated 

 by material forced to flow under it from below the contracting area. 

 It seems to me very like the case of a man trying to lift himself up 

 by pulling at the chair he is sitting upon. 

 Park. Couner, Blundell Sands, Liverpool. T. Mellard Ebade. 



WILLIAM TOPLEY, F.R.S., F.G.S. 



Born March 13th, 1841. Died September 30th, 1894. 



(With a Portrait.) 



William Topley was born at Greenwich, on March 13th, 1841 ; 

 and after gaining his early education at local schools, he received, 

 during the years 1858-61, the valuable scientific and practical 

 training of the Royal School of Mines. 



In 1862 he was appointed an Assistant Geologist on the Geological 

 Survey, when Murchison was Director- General, and Ramsay was 

 Local Director for Great Britain. He then commenced field-work 

 under the guidance of Dr. (now Professor) Le Neve Foster, who, 

 with others, was engaged in the Survey of the Wealden area. 

 There he was initiated into the methods of geological mapping 

 among the changeful Hastings Beds, at Mayfield and other places 

 between Burwash and Lindfield, to the south of Ashdown Forest. 

 There, too, in course of time, he gained a detailed knowledge of 

 the Cretaceous and Neocomian formations, and his interest was 

 aroused in questions of Physical Geology, to which for many years 

 he gave particular attention. 



