366 Petty: Early Notices of Yorkshire Hydrozoa. 
Further, the cycle of events as pictured by Mr. Reid, explains 
not only where the Yorkshire coast boulders go to, but also 
where those on the Lincolnshire coast come from ; and in reject- 
o sho 
in the boulder-clays of Lincolnshire is not enough. It must also 
be shown that such clays are found in places where they are 
exposed to marine erosion. The distribution of the boulders 
along the Lincolnshire coast is also a point of importance, and 
here the large shingle beach of Donna Nook is a crucial test. 
The stones there cannot have come from the warp-covered shore 
of the Humber, and any accumulation of boulders derived from 
the Lincolnshire coast itself must be sought southward, not 
in the extreme north. : 
There is one more significant point which has been over- 
looked. The Lincolnshire coast boulders, according to Mr. 
Burton, are mostly of small size: of the twenty specimens 
which he has described, none measured more than five inches. 
This accords with the supposition that they have travelled far. 
he boulders embedded in the Lincolnshire boulder-clay, as 
7 
a foot in diameter. A collection of boulders on the shore, if 
derived from an immediately local source, ought to have a fair 
proportion, and indeed more than a fair proportion, of the large 
ones. This is the case on the Yorkshire coast; but, so far as 
our infee ee goes, it does not seem to be the case in 
Lincolnshire. 
<-> 
NOTE—-H ee wae 
Early Notices of Yorkshire Hydrozo ot know how many 
references there are in e Naturalist’ to ‘Satine sa? Hydr ozoa, and 
the following may have already been entered as old records for that place. 
The mode me iv! at 
Sertularia Heats a E.& Ti is cheaiane found on the coast of Scar- 
borough, in Yorkshire.’ Ellis & ee » Nat. Hist, of Zo paige Soa 
1.786, p. 8% es name, Hincks’ H. a a 265, ‘Common . Sca 
borough, Filey, ete.’ 
Sertularia jon essina L. * The ‘Se wie agg ook s name] is hiefly 
found in “ih water on yi: coast of Yorks! , Ellis & Solander, 
p- 39. incks, p. 7% says, ‘Common on Vormskive pias 
Thuiaria a thuja L ‘They are found on the noe i mer and in ei 
North of England, particularly about Scarbor the fishe cae 
have given them the name of Bottle- sdlesr ene Ells, Polat 1755» P- 
A prevalent northern form, mcks H. 2,4 
Plumularia frutescens E.&S. ‘This Comins} was found 7 Seater 
Ellis & Solander, 1786, e 55 as gota f. Hincks’ 308, says, 
‘Rare on Yorkshire Coas as dredged it at Sa hore = 
S. L. Petty, Ulverston, ced Nodiaibe aoe 
ae 
Naturalist, 
