Mr. R. MacAndrew on the Mollusea of Vigo Bay. 507 
L.—On the Mollusca of Vigo Bay in the North-west of Spain, by 
~ Roserr MacAnprew, Esq., F.L.S., in a Letter to Professor 
Epwarp Forsss, F.R.S. 
To Richard Taylor, Esq. 
Dear Sir, May 1849. 
I senp you a letter which I have lately received from Mr. Mac- 
Andrew, whose zeal in the cause of natural history has induced 
him to undertake a voyage in his yacht to Spain and Portugal, 
with the intention of exploring the sea-coasts of those countries 
by means of the dredge. The facts he has already brought to 
light, as mentioned in the following letter, are of the greatest 
interest both in a natural history and a geological point of view. 
His discovery of an isolated littoral marine fauna (and probably 
marine flora also) of a British or Celtic type imtersecting the 
Lusitanian province, reminding us of the boreal outliers in our 
Own seas, appears to support in an unexpected manner the theo 
I proposed in my memoir “On the Geological relations of the 
existing Flora and Fauna of the British Isles,” published in the 
‘Memoirs of the Geological Survey of Great Britain for 1846,’ 
’ wherein I maintained the former existence during the pliocene 
and pleistocene epochs of “a geological union or close approxi- 
mation of the west of Ireland with the north of Spain.” This I 
argued from the botanical features of Ireland and the Atlantic 
Islands, and from the geological phenomena which had occurred 
within the area in question since the eocene epoch. Had such a 
connexion existed, even as by means of it we had an Asturian 
flora transmitted northwards to Ireland, so along the coasts of 
the same land, littoral forms of mollusca, especially during the 
glacial period, when the tendency of conditions was to diffuse 
northern species southwards, would in all probability have been 
transmitted to the coasts of Spain. In no other way can we ac- 
count for such a phenomenon as that made known in Mr. Mac- 
Andrew’s letter. His discovery in Vigo bay of a colony of re- 
versed Fusi, a race so characteristic of the red crag, supports this 
view most strongly, for in the southernmost beds of the Irish 
drift we find Fusus contrarius associated with a Spanish Mitra 
and Purpura lapillus, in the neighbourhood of the remains of a 
terrestrial flora of the Asturian type. 
I remain, dear Sir, very truly yours, 
Epwarp Forses. 
Faro, 8th April, 1849. 
We sailed from Portsmouth on the 9th and entered the port 
of Vigo on the 14th ult. Being ordered to perform a quarantine 
of ten days, we proceeded at once to the Lazaretto of St. Simon, 
