During September, 1940, there were many falls of earth and other things upon the roofs of London. An example that I had excellent opportunities of studying consisted of loam, and gravelly loam, distributed in discrete patches over an extensive area. The material must have fallen from a considerable height, for everywhere it moulded itself with flat base to suit its foundation; and, whether forming mere pellets or splashes a few feet in diameter, it developed a surprisingly uniform summit level of little more than 1 inch in height. On breaking the loam across, one always found a system of close, roughly horizontal cracks, a type of rude joint cleavage. This structure persisted despite frequent wettings and dryings, even though when wet the loam became quite sodden.

A Recent paper in this journal by K. P. Oakley (1940) has drawn attention to certain structures in Recent rhyolitic ashes of Malaya, and contraverts the earlier view that these structures represent sponge spicules. Oakley suggests tentatively that most of them are the casts of minute spherical and tubular hollows in the material of the ashes. It may be of interest, therefore, to describe comparable material from New Zealand which appears to support this suggestion.

In 1838 Johnston in the first edition of his History of British Zoophytes instituted a genus Lepralia (the middle a should from its derivation be short) with seven type species—Cellepora hyalina Linn., Berenicea nitida Flem., Berenicea immersa Flem., Cellepora coccinea Abild., Eschara ciliata Pall., Discopora trispinosa Johnst., and Lepralia variolosa nov. The genus has had a very chequered career, as well as very heavy use.