Correspondence — Dr. R. S. Traquair, F.R.S. 95 



a microscope. Tlie plate became uniaxial at 95° C. — A, Hutchinson : 

 On a total-reflection diagram. From this diagram the refractive index 

 of a substance is graphically determined when given the angle of total 

 reflection with respect to a known substance of higher refractive index. 

 By taking the sine of the angle as co-ordinate the curves are straight 

 lines. — T. Crook : The occurrence of Ankerite in Coal. The white 

 crystalline layers often found as infillings of the vertical joints in 

 British coal are ankerite. Dolomite was not found and calcite occurs 

 sparingly as compared with ankerite in the specimens examined. 



coi^iREisiPOisrnDEisroE]. 



THE WEALDEN FISHES OF BEENISSAET. 



Sir, — I greatly regret that the names of new species described by 

 me in my recently published work on the Wealden Fishes of 

 Bernissart (Mem. du Musee roy. hist. nat. Belgique, May, 1911) have 

 been antedated by three years. 



The cause of this was that the plates, which contain the explanation 

 of the figures as well as the figures themselves, were printed off in 

 1908, it being expected that the work would be published in the same 

 year. Unfortunately my MS. was not ready in time, and publication 

 was delayed until last year, and then, in going over the proofs, I ought 

 to have corrected the dates in the letterpress, inserting a note of 

 explanation of the matter. Here I committed the mistake of 

 imagining that the date 1911 on the title-page cancelled the date 

 1908 in the text and on the plates, never thinking that the reader 

 would thereby be led to suppose that these new specific names had 

 already been published in a preliminary Note, which is not the 

 case, and the proper date of publication of the names in question is 

 May, 1911. 



Ramsay H. Traquair. 



CoLiNTON, Midlothian. 



HUMAN AET IN THE EED CEAG. 

 Sir, — In his recent communication ' to the Royal Society Sir E. Ray 

 Lankester gives an account of the discovery, below the Red Crag of 

 Suffolk and the Coralline Crag, of human tools — flint implements. 

 If there were tool-using men living while the basal deposits of the 

 Red and Norwich Crag were being laid down, we should not find it 

 hard to believe that there were men living while the mass of the 

 Red Crag was deposited ! Consequently the position taken up by the 

 late Henry Stopes as early as 1881 is vindicated. In that year he 

 read a short paper before the British Association, giving an account 

 of a remarkable shell, engraved with a rude portrait of the human 

 face, found in the stratified deposits of the Red Crag.^ At that time 



^ See Geol. Mag., December, 1911, p. 576. 



2 H. Stopes, "Traces of Man in the Crag " : Brit. Assoc. Eep., 1881, p. 700. 



