The progress of modern discovery, both in Palæontology and Zoology, has been steadily tending to bridge over the gap which seemed at one time to separate the past from the present life-history of our globe, and has brought each more closely into relationship with the other than seemed possible fifty years ago.

In a paper entitled “On Minerals new to Britain,” published in the Mineralogical Magazine, vol. v. p. 1, Professor Heddle mentions the occurrence of a bastite-serpentine at two localities in Aberdeenshire; one in the parish of Belhelvie, the other on the shore close to a curious rock named the Black Dog. A visit to the localities has enabled me to add to his account some particulars, and to offer one or two corrections which seem to me not unimportant.

In the first place, let us obtain a clear idea of a Graptolite, and for this purpose we will consider two members of the family Dichograptidæ, namely, Didymograptus vacillans, Tullb. (Fig. 2, p. 452), and Dichograptus octobrachiatus, Hall (Fig. 1, p. 449).

This is the third of M Coy's original species. The specimen in the Cambridge Museum has its carapace ovate-oblong or somewhat boat-shaped in outline, 50 mm. (2 inches) long, 18 mm. high; moderately convex; straight or very slightly arched above and more strongly arched below (both edges are partly imbedded in the matrix of the original specimen, b/5, M Coy's fig. 4). The anterior end (damaged) was neatly rounded, sloping up gracefully from below. The posterior is obliquely truncate from above downwards and outwards, with the postero-dorsal angle distinct, and the posteroventral angle prominent and blunt. There is no eye-spot. Traces of longitudinal striæ are visible on the impressions of the valves in the grey, micaceous, Upper-Ludlow sandstone, from Benson Knot, near Kendal, Westmoreland; two specimens (one of them good) are in the British Museum, No. 44342, from the same locality.