1914-15.] Fossil Micro-organisms. 127 
sented the appearance of a closely set meshwork, the walls of which were 
suffused with the reddish-brown ferric hydroxide, whilst the spaces between 
were either empty or else filled with greenstone. At some points, however, 
there were in them bits of organic substances in various stages of decom- 
position. A very good example is shown in fig. 8, Plate II, which shows 
one of these meshes in which the original organic remains had been almost 
completely demolished when the process of petrification set in. Under 
the microscope is seen precisely what, under similar circumstances would 
be seen to-day in a similar piece of organic remains, viz. several species of 
bacteria with one predominating over the remainder. In this case the 
predominance has been secured by the organism which we may name 
Bacillus I (Gault). 
Bacillus I {Gault ). — Average width about J /x (*0005 mm.); length, 
100 fj. and over together with all sizes from IJ ^ upwards. Its bacillary 
nature is obvious from its shape, size, and method of disposition in the field 
(figs. 18 and 19). I mention the last-named point because, if these marks 
seen in fig. 8, Plate II, had been artificially made, the disposition of the indi- 
viduals would not be similar to those seen in this plate, but would rather 
tend to point all in one direction. The individuals of a bacterial com- 
munity, on the other hand, normally point in all directions. The organism 
was too small to enable any further details of its structure to be deciphered. 
In fig. 19 is shown what appears to be a rod which has split up into four 
daughter-rods. It was impossible to determine whether the method of 
division resembled that employed by modern bacilli, in which transverse 
walls thrown across the cell precede cell division, or whether division took 
the form employed by spirillar bacteria and by the sulphur bacteria, in 
which simple fission is the mode. The determination of this point is ex- 
tremely important for the ph^dogeny of the group, for it would determine 
the broad lines on which evolution had taken place. 
Bacillus II {Gault) (see fig. 20). — This organism was found in the 
same place as the above, but was larger in size, being about 1 im broad, and 
on the average 5*7 /x long. The rods had well-defined membranes, and 
rounded ends. This organism evidently was not playing an important role 
at the time when all growth had come to a stop. 
Micrococcus I {Gault ). — If any doubt existed as to whether the bodies 
under examination represented bacterial growth or not, it would be set at 
rest by the observation of these forms. In fig. 21 are represented indi- 
viduals which belong to the coccus group of bacteria (Coccacese). Here 
we see not only the unicoccus but also diplococci in various stages of 
formation. We see the preliminary constriction which in modern cocci 
