The working-place in such case is considerably narrower than in rooms or stopes, and there is also greater difficulty in supporting the roof because the projecting beds tend to break close to the point of support where the strain is greatest.
When the roof is weak, or when it is undesirable to leave so much ore in the stopes, false stulls are sometimes erected in the upper part of the stope.
In this method of mining the different stopes must be kept close together; otherwise there is much added labour in shovelling the broken ore down to the main level.
This method has the advantage of permitting the ore to be sent to the surface as fast as it is mined instead of being left for some months in the stopes for the men to stand upon.
Divided into three or four stopes at varying heights above the main level, the lowest being known as the cutting-out stope, the others as the first and second back stopes in ascending order.
A thorough examination of cycadean seeds has recently been made by Miss Stopes, more particularly with a view to a comparison of their vascular supply with that in Palaeozoic gymnospermous seeds (Flora, 1904).
(1898); Wieland, " American Fossil Cycads," Carnegie Institution Publication (1906); Stopes, " Beitrage zur Kenntnis der Fortpflanzungsorgane der Cycadeen," Flora (1904); Caldwell, " Microcycas Calocoma," Bot.