106 
DISCOMYCETES OF THE BIRMINGHAM DISTRICT. 
Now, there have been, within historic times, two previous 
subsidences similar in kind to that which has just occurred— 
the one about 400 years ago, and the second 100 years since. 
On both of these occasions the subsidence appears to have 
been initiated by engineering operations, by which the level 
of the waters of the lake was suddenly lowered, and, as a 
consequence, the support they gave to the ooze removed. On 
the present occasion, the theory is that the accumulation of 
buildings had exerted such an increasing pressure on the upper 
stratum, that the weight was sustained with difficulty ; that a 
condition of unstable equilibrium resulted, and that this 
unstable equilibrium was disturbed by some pile-driving 
operations which were proceeding in connection with the 
formation of a new pier. It is supposed that tbe concussions 
arising from this cause disturbed the pressure and the firmness 
of the supporting medium, and that the ooze, having lost some 
of its support, slid forward, and let down the strata above, 
bringing with it the houses, &c., that were erected on its 
surface. 
THE DISCOMYOETES OF THE BIRMINGHAM 
DISTRICT. 
BY W. B. GROVE, B.A. 
The publication of Mr. Phillips’ Manual of the British 
Discomycetes affords a good opportunity for the revision of 
the species of that group which have been noticed in the three 
counties of this district. The following list is founded chieflv 
on the specimens preserved in my own herbarium, but to 
make it more complete, all the other species of which I can 
find trustworthy records have been added. 
The total number contained in the “ Manual ” is 615, of 
which a few over one hundred, or a sixth part of the number 
found in the whole British Islands, have as yet been discovered 
here. It will be noticed that the Discomycetes, in Mr. 
Phillips’ acceptation of the term, embrace some species which 
have been usually regarded in this country as more closely 
allied to the Hysteriacefe. 
I have marked with an ( = ) those of which I myself 
possess specimens, all of which have been carefully revised 
and compared with the descriptions in the “ Manual.” Many 
of these have been confirmed or named by Mr. Phillips 
himself, to whose constant and willing help I take this oppor¬ 
tunity of acknowledging my indebtedness. The records 
