300 SHEPPARD : MARTIN SIMPSON AND HIS GEOLOGICAL MEMOIRS 
The preface to this work, dated " Whitby, Feb., 1843," is not without 
interest, and shows that in those early days attention was paid to the 
law of priority in nomenclature. Notwithstanding what Simpson says 
as regards illustrations, it is a great pity that the suggested plates 
were not prepared, as much subsequent confusion would have been 
avoided. He writes : — 
" Nearly the whole of this work was written two or three years ago, 
while I was arranging the AVhitby Museum, and had favourable oppor- 
tunities for observation ; and its appearance has been delayed wholly 
from the want of some convenient means of publication. To those, 
therefore, who have aided me by their subscriptions, I feel the more 
grateful. It would have given me pleasure to have obliged my friends 
by the addition of plates, but the general forms of the genus have 
already been well illustrated in that way by others ; and the best 
figures can do but little in representing specific characters. 
"Some ot the names, perhaps, may appear objectionable. But where 
I did not observe a name inharmonious, or conveying a wrong character, 
I thought it better to let it pass, than to invent a new one. In all 
cases, to the best of my knowledge, as a matter of justice, I have adopted 
the names of previous authors, and I have also paid the same respect 
to the excellent manuscript names of my friend Mr. Bean. It may 
appear surprising that so many species of ammonites should occur in 
one group ot strata, and in one small district, but so far from having 
over-rated the number, I believe that when these fossils shall be more 
generally studied, and fresh localities shall have been carefully examined, 
the number of species will be still further increased." 
As specimens of his descriptions, below are given his accounts of 
two well-known species, A. heterophyllus and A. elegans : — 
[page 7] I. Without a dorsal keel or furrow. 
a. No spines. 
1. A. HETEROPHYLLUS, Soii\ Syu. N. Whithieusis, Y. and B. 
Rather depressed ; inner volutions concealed, outer whorl the 
diameter ; umbilicus small ; strife numerous, annular, diverging ; 
aperture ovate : diameter 1 to 16 inches. 
This ammonite may be readily distinguished from all the others of 
this group, except the next, by the inner whorls Vjeing entirely concealed. 
