TRANSACTIONS OF THE SECTIONS. 71 
fact about these nodules is the abundance of a Black Crag or Diestien shell, Iso- 
cardia lunulata. he shell does not occur in either Red or Coralline Crag; but out 
of every forty nodules with fossils in them, you have seven specimens of Isocardia. 
Even Jsocardia cor is most rare in our English Crags, Only hal? a dozen speci- 
mens have been found altogether in the Coralline and Red Crag. The presence of 
this shell in these nodules proves that the nodules are bits of a very different 
deposit, and probably of a Diestien age, not necessarily of exact equivalence with 
the Belgian Black Crag. We know how much a few miles of distance may affect 
a marine fauna; and it is most probable that the Suffolk deposits were always 
littoral or sublittoral, while those of Belgium accumulated in deep water. These 
nodules, which probably are of great importance, are supposed by some to be of 
indurated Coralline or Red Crag—by Mr. Searles Wood and, the author believed, 
by Sir C. Lyell; but a careful examination only is required to convince any one 
that such is not their mineral structure, and that the shells and bones they contain 
are those of Diestien age. The ditference between the Diestien fauna and the 
Red and Norfolk Crag fauna is very great. Great changes as to glaciation have 
gone on between the two. The Coralline Crag bridges over the break in part, as 
does the yellow Antwerp Crag. The presence of derived Mastodon-remains in 
the Red and Norfolk Crag, and of Diestien Cetacea in the Red Crag too, is always 
most deceptive, and tends to mislead the judgment as to the true character of 
those beds. 
On the Range and Distribution of the British Fossil Brachiopoda*. 
By J. Loan Losrry, F.G.S. 
This paper was read in explanation of a series of Tables exhibited to the Section, 
and prepared with the view of showing, by a new arrangement, the range, disiri- 
bution, increment, decrement, and maximum development of each subgenus, genus, 
and family, as well as of the class of Brachiopoda in British straia. The paper 
contained a summary of the results shown by the Tables, and was accompanied by 
lists of the species hitherto discovered in each formation, or minor group of rocks, 
in which the class is represented. 
The first of the Tables gives the range and distribution of each genus, the genera 
being arranged in the order of their incoming or earliest appearance in British 
strata. The number of species of each genus in any geological formation is repre- 
sented by short thick lines, each of which indicates the presence of one species. 
These lines are so arranged that the increment, decrement, and maximum deve- 
lopment of each genus is distinctly shown, and the number of species of each genus 
in each formation in which it appears may be at once ascertained. 
The second Tabie gives the genera arranged according to their family alliances, 
and shows the family to which each genus belongs, the order in which each family 
has appeared, and the number of species as well as of genera in every formation in 
which the family is found. 
The third table is a summary of the second, in order to show more distinctly 
the increment and decrement of each family without reference to its genera, each 
line representing a species as in the other Tables. 
The fourth Table is a summary of the third, to represent at a glance the relative 
importance of the representation of the class Brachiopoda in each geological 
formation. 
The following are some of the more prominent results shown by these Tables. 
OF the forty-seven genera and subgenera, eleven are represented by species now 
living in the seas of our globe, and are therefore recent as well as fossil genera. 
Of these, Discina, Lingula, Crania, Rhynchonella, and Terebratula range from 
Paleozoic rccks. The genera Leptena, Spirifera, and Spiriferina range from 
Palzeozoic inio Mesozoic, but do not reach Cainozoic strata, while each of the 
following twelve genera is characteristic of a single formation :—Kutorgina (Lin- 
gula flags), Acrotreta (Llandeilo), Orthisina (Caradoc), Orbiculoidea (Wenlock), 
Nucleospira (Wenlock), Merista (Middle Devonian), Uncites (Middle Devonian), 
* Some of the details of this paper are given in the Geological Magazine for November, 
1868, vol. v. p. 497. 
