96 Correspondence — Mr. Dahyns. — Obituary — T. Sopwith. 



require. I will only remark that an interesting analogy may be 

 traced between the evaporation of the water of the ocean and the 

 impulsive motion of the Gulf Stream, both alike due to solar heat ; 

 only the vapour is liable to be converted into snow much nearer 

 home ; but the Gulf Stream rolls on till its heat is expended and it 

 is converted into ice, and so its function in the economy of Nature is 

 discharged, which may not at present have been fully appreciated. 

 25, Prince of Wales Road, Norwich, John Gunn. 



January 15, 1879. 



THE HITCHING STONE. 



Sir, — In the British Association Report for 1874, page 196, the 

 " Hitching Stone " on Sutton Moor, near Keighley, is described as a 

 boulder. As I surveyed that country, I may perhaps be allowed to 

 say that in my opinion the Hitching Stone is not a boulder. It is 

 simply a block of Millstone Grit, weathered in place, the rest of the 

 layer having, in the immediate neighbourhood, been removed by 

 denudation. In a broad sense, it forms part of the massive grit of 

 which Hitching Stone Hill is composed. The stone stands on the 

 escarpment of this grit, the base of which is marked by Hitching 

 Stone Spring, about 30 feet below. This bed of grit is considered by 

 my colleagues and myself, on stratigraphical grounds, to be a 

 portion of the Rough Rock. Hanging Stone Quarry is in the grit of 

 Earl Crag, which is the principal bed of the Third Grit Series. 



The most remarkable thing about the Hitching Stone is that it is 

 perforated by a large hole, out of which a tree, a Lepidodendron as 

 far as I remember, has weathered. A vertical section across the 

 hole is of an oval shape, measuring 15-| inches b_y 12, the longer 

 axis horizontal or rather along the bedding plane : thus we see the 

 flattening produced by the weight of the overlying sand on the 

 decaying trunk ; and we also see that the stone is standing in its 

 original position in the bed of grit of which it formed a part. 



Bridlington Quay. J. R. DakynS. 



OBITUABT. 



THOMAS SOPWITH, M.A., F.R.S., F G.S. 



Born 1803. Died 1879. 

 We regret to announce the death of Mr. Thomas Sopwith, F.R.S., 

 at Westminster, on the 16th January last. He was born in 1803, 

 at Newcastle-on-Tyne, and was for nearly 50 years extensively 

 engaged as a civil engineer in mining, railway, and other works, 

 both in this country and on the Continent, and was the author of 

 several works on architecture, isometrical' drawing, and mining. In 

 1838 he was appointed Commissioner for the Crown under the Dean 

 Forest Mining Act, and in the same year a communication made by 

 him to the British Association led to the establishment of the 

 Mining Record Office. He was a member of many of the leading 

 scientific societies, and one of the early members of the Institution 

 of Civil Engineers. — Daily News, Jan. 17, 1879. 



Erratum. In Mr. Dakyns' letter in the Geol. Mag. January, 1879, p. 46, 

 line 1 1 from bottom, the words river base should have been river Ouse. 



