THE YORKSHIRE NATURALISTS’ UNION AT ASKERN. 285: 
sheets of water. At Shirley Pool in particular the edge of the 
water was in many places out of reach of collectors, an expanse 
of soft mud intervening between it and terra firma. n the 
whole it was perfectly evident there was not much to choose 
between the 1887 and 1893 excursions. On the present occasion 
the Section was fairly well represented, as, in addition to its two 
hon. secretaries, the party included Mr. W. Denison Roebuck,. 
F.L.S., Mr. W. Rushforth, and Mr. J. E. Crowther. Mr. Roebuck 
selected the route to Campsall Woods, and the others proceeded 
along Askern Pool to Shirley Pool and Jungle, under the 
guidance of Mr. W. Nelson, who had previous knowledge of the 
district. The dyke running off Askern Pool had been specially 
noticed for its albino varieties, but even with the aid of Mr. Nelson, 
who has collected them in byegone years, not the slightest indication. 
was seen to be exhibited in any of the specimens of Zimn@a feregra 
or Limnea palustris, which were all very eagerly examined in hope- 
ful anticipation of meeting with this interesting variety. At the end 
of the path we turned into the field which had been mentioned as 
containing some important lacustrine remains and an examina- 
tion of the mole-heaps, which are very numerous, resulted in the 
discovery of Viviparus contectus, a species supposed to have become: 
extinct in the district. A few moments’ attention was enough to 
convince the party that Viviparus had once been very common and 
that by its numbers and surroundings it might still survive in the 
neighbourhood. Of this, however, we were not able to satisfy our- 
selves. The drain fronting the field had been cleaned out and its 
Tejectamenta did not reveal the remains of this species, although 
many common species were well represented. It is true an old shell 
was taken out of the drain, but it did not seem to be proof that it 
had not been dropped into the water, as on the ground only a few 
ards off numerous loose specimens were deposited. There can be: 
\ little doubt: that ‘excessive cleaning of the drains and dykes is 
- : inimical to the well-being and propagation of the species, and that as 
districts in which it is known to occur become more and more 
cultivated the less likelihood will there be of its continuing a member 
Ss of their fauna. As we were not satisfied that the shell had been oo ‘a 
ed from the drain we proceeded to carefully examine the soil cee 
the field. These operations soon gave us ample evidence of the — 
existence at one time of an extensive marsh or lake, in which a good — 
a variety of mollusca had lived. In fact several good sections were ca . 
procured with shells scattered through the peaty clayand marl in 
: _ cliffs cliffs of the cereemiowan coast. One or two sections were exc 
situ corresponding exactly to the lacustrine deposits exposed a bl a 
