650 
DR. J. W. DAWSON ON ERECT TREES CONTAINING ANIMAL 
gentle elevation of both, front and hind margins, hut with no anterior ridge. In 
neither of these species could any trace of spines be found. 
Besides the myriopodal remains, there are a dozen fragments that must probably 
be referred to Scorpions. Of some of them there can be no doubt. The remainder 
are mere bits of integument showing the surface sculpture, but often with no natural 
borders whatever. In the character of the surface there is such difference as to 
indicate more than a single species. For though we should certainly expect to find 
considerable differences between the various parts of one and the same individual, the 
diversity here is too great, both in amount and nature, to render it at all probable 
that the difference may fairly be explained in such a manner. The better fragments 
exhibit a considerable portion of the stouter part of the body, enough to show its 
general form at least, and these point also to the probable existence of two species, 
of nearly the same size, but differing in form and sculpture ; the more fusiform-shaped 
species having a less roughened surface than is found in the more parallel-sided form. 
The latter agrees tolerably with the carboniferous genus found near Mazon, Ill., called 
Mazonia by Meek and Worthen, and certainly belongs to the same group of 
Scorpions ; but in view of the remarkable addition to our knowledge of the car¬ 
boniferous Scorpions in the promised publication of the researches of Mr. Peach of 
the geological survey of Scotland, further study of these remains will best be 
postponed. In the meantime, they add another form of strictly land life to those 
already found in these remarkable repositories of fossils, and perhaps illustrate the 
utility of the bony and horny armour of the smaller Batrachians of the period, which 
may have had to contend with these active and venomous Arachnidans. 
The occurrence of seven species of Millipedes in a few decayed trees in one locality, 
in connexion with similar discoveries in other parts of the world, tends to strengthen 
the probability of the suggestion, already made by Dr. Dawson, that the animals of 
this type may have culminated in the Palaeozoic period. 
