416 
It was Lonsdale who pronounced definitely that the Stonesfield 
Slate is subjacent to the Great Oolite, our grand Bath Stone.. 
(Proc. Geol. Soc., I. 414.) It was Lonsdale who satisfied 
Sedgwick and Murchison that the hard beds in Devon and 
Cornwall, above the Silurian and below the Carboniferous forma- 
tions, were the equivalents of the Old Red Sandstone in Scotland 
and who, in 1837, was directly instrumental in establishing the 
adoption of the new term “ Devonian.” (Lyell’s Elements, 531 ; 
Geikie’s Murchison, I. 264.) When Dr. Buckland gave his assent 
to its use, his memorable words were : “‘ Henceforth there will be 
two great names in English geology, William Smith and William 
Lonsdale.” (Geikie, I. 267.) In the yet more important 
Silurian system, considered so exclusively Murchisonian, Lonsdale 
is entitled to very honourable mention, as we learn from the 
testimony of Professor Phillips. These are his words as given 
by Sir Archibald Geikie in his life of Sir Roderick Murchison :— 
“Perhaps no one better than Lonsdale comprehended the true 
meaning of the work which Murchison undertook. Certainly no: 
one gave more effectual assistance in the often delicate task of 
clearing up in the calmness of the closet the difficulties which 
frequently misled the eager enthusiast in the field. Murchison 
was never slow in acknowledging his great obligation to his 
patient and right-judging friend.” (I. 220). 
The name of Lonsdale is attached for all time to a singular 
fossil, Diceras Lonsdalei, belonging to the Arietide or Ram’s. 
horn division of the Ammonites, which is found only in Wiltshire, 
in those ferruginous sands which cap the high grounds above 
Bowood, near their intersection by the Wansdyke.  (Lyell’s 
El., 342.) Godwin-Austen in 1854 specified Stock Orchard near 
Calne as the particular locale of the Diceras (Q.J.G.S., VIL. 469) 
and I went there in 1872 in search of specimens, meeting with 
poor success because the pit had been closed. We have one 
specimen in our Museum. Finer examples may be seen in the 
rich Museum at Devizes, presented by Mr. Cunnington in 1875. 
(Wilts Nat. His. Mag., XV. 137.) 
