THE ANNALS 
AND 
MAGAZINE OF NATURAL HISTORY. 
[FIFTH SERIES.] 
No. 16. APRIL 1879. 
XXVIII.— On the Geological Distribution of the Rhabdophora. 
By Charles Lapwoeth, F.G.S. 
Part I. Historical. 
Introductory. 
The present paper was partly written in the autumn of 1873, 
as a sequel to my memoir on the Improved Classification of 
the Rhabdophora, which was published in the 1 Geological 
Magazine ’ of November and December of that year*. Its 
original purpose was to show that what are there classed as 
closely allied genera are invariably associated in synchronous 
deposits in widely separated portions of the Lower Palaeozoics 
of the northern hemisphere—the justice of the classification 
there proposed receiving in this way a most striking confirma¬ 
tion. I have deferred its publication from time to time, hoping 
to be able to include the general results of a personal study of 
the Gi’aptolite-bearing beds of Wales and the West of Eng¬ 
land. This investigation, however, I have hitherto been unable 
to accomplish, owing to my want of leisure and to the all- 
absorbing nature of my work among the Lower Palaeozoics of 
the South of Scotland. In some respects this delay has been 
an advantage; for during the interval the progress in many 
departments of research among the Palaeozoic rocks has been 
* Geol. Mag. vol. x. dec. 1, pp. GOO, G5G. 
Ann. & Mag. N. Hist. Ser. 5. Vol iii. 
17 
