KIRKBY — SANDPIPES IN MAGNESIAN LIMESTONE OF DUKIIAM. 293 
and I need only remind you of M. Gi'uencwalds' papers on Bogoss- 
lowsk. At the locality Petropawlowsk the proportion of the total 
BracLiopoda and Corals to all the rest of the fossils is twenty-six to 
one, or nearly seven and a-half to one ; at Bogosslowsk eighteen to 
one, or two. In the middle zone, as given by the fossils common to 
the "colonies" and E in Bohemia, this proportion on the contrary is 
twelve to forty-eight, or one to four. At Bogosslowsk and Petropaw- 
lowsk not one member of group A is found ; not even a single Orthis. 
M. Barrande, in his paper on the parallel between the Silm'iaii 
deposits of Scandinavia and Bohemia, has shown that dm-ing the 
first periods of animal life, the species were already not universally 
spread, but distributed according to the same strict rules which regu- 
late the disti-ibution of organic beings in our days. Convinced as I 
am of the correctness of this view, I venture to add that in remote 
times also the distribution of the species was not only horizontally 
but also vertically limited, i. e., that not only geographical provinces 
but also bathymetrical zones have existed in the Silmian seas. 
In closing this abstract, I beg you, my dear friend, to remark, 
that for the sake of shortness some view may be put forth here 
too apodictally, which is only enounced as a mere conjecture in my 
paper, and many an argument in favour of my views has been 
omitted ; I beg also to observe this to any one of your friends, to 
whom these lines might seem to you worth communicating. Impos- 
sible as it is to arrive at decided conclusions by the study of one single 
class, I have only intended to show that fossils may no more be re- 
garded as mere " dead-bom medals," but must always be looked upon 
as the remains of living beings, the existence of which depended 
upon a thousand external conditions. 
I am, my dear friend. 
Most truly yours, 
To Thos. Davidson, Esq., F.G.S. Edw. Suess. 
ON THE OCCURRENCE OP "SAND-PIPES" IN THE 
MAGNESIAN LIMESTONE OF DURHAM. 
By J. W, KiEKBT. 
During the past year my attention has been directed to some 
curious tube-like cavities in the magnesian limestone near Sunder- 
laod, which I beheve to be perfectly analogous to the sand- and 
gravel-pipes of the chalk districts of the south of England and 
France. And as our knowledge of such pipes has hitherto been, 
almost confined to their occm'rence in the chalk, I deem it advisable 
to describe these in the magnesian limestone ; not that they add 
much to what we already know, or that they afibrd grounds for a 
