Obituary — Thomas Roberts, F.G.S. 14L 



Lower PalEeozoic Rocks of the neiglibourhood of Haverfordwest/- 

 because in that he was associated with the keenest stratigraphical 

 paleeontologist we have, on ground which he, rather than Roberts, 

 has made peculiarly his own. Whatever Roberts's contribution to 

 that work may have been, he must have come out of it a stronger 

 man from the contact. But in his description of the Jurassic Rocks, 

 we see in one paper after another first that careful working out of 

 zones in one connected set of sections, and then suggested correlation 

 of horizons between more or less widely separated areas. 



He fi.rst undertook the examination of the Jurassic Rocks of the 

 neighbourhood of Cambridge, upon which he wrote an essay, for 

 which the Sedgwick Prize was awarded to him in 1886. It was 

 hoped by his friends and by himself, that this essay would some 

 day be expanded into a much larger work, or at any rate that its 

 scope might be considerably extended. As it stands, it is a valuable 

 contribution to the Life History of the Earth, and, for students of 

 the geology of the neighbourhood of Cambridge, a useful handbook. 

 The Syndics of the University Press have undertaken to publish it, 

 and many friends have volunteered their services to help to see it 

 through the press in Memoriam. 



In the following year he read a paper before the Geological 

 Society,^ " On the Correlation of the Upper Jurassic Rocks of the 

 Swiss Jura with those of England." This was the outcome of an 

 excursion for which he received a grant from the Worts Fund in 

 1884. In it he gives a detailed description of the more important 

 subdivisions above the horizon of our Kellaways Rock, with 

 numerous sections, and full lists of fossils. He points out that the 

 thick clays of Kimeridge and the variable beds of Portland and 

 Purbeck are in the Jura all represented by massive limestones and 

 that, as might be expected from such difference of sediment, there 

 is a considerable difference in the fauna of the two areas, but that 

 still some well-marked zones make an approximate correlation 

 possible. The views of various authors and his own as to the 

 identity of certain widely separated zones, he presents tabulated in 

 parallel columns for easy reference, and explains wherein he differs 

 from the continental geologists as to the synchronism or the group- 

 ing of the several deposits. 



In 1888 the Lyell Fund was awarded to him in token of appre- 

 ciation of these investigations. Having thus prepared himself for 

 the recognition of the different horizons in the Jurassic Rocks, even 

 when presenting very various aspects, he turned his attention to 

 " the Upper Jurassic Clays of Lincolnshire," ^ and traced through 

 that district a zone which had not been previously recognized, and 

 which he identified with certain clays in the neighbourhood of 

 Cambridge, referred by him to the Corallian. 



The thorough way in which he worked out a paleeontological 

 inquiry may be gathered from his early note * on what he considered 

 a new species of Conoceras from Llanvirn. He described the 



1 Q.J.G.S. vol. xl. 1884, p. 476. - Q.J.G.S. vol. xliii. 1887, p. 229. 



3 Q.J.G.S. vol. xlv. 1889, p. 545. , ^ Q.J.G.S. vol. xl. p. 636. 



