By A. J. Jukes-Browne, B.A., F.G.S8. 335 
are not agreed as to the line of demarcation between the two. 
Even if we follow Professor de Lapparent, who makes the Albien 
include the zone of Ammonites inflatus, we could not adopt that 
name for an English group which also includes the zone of Pecten 
asper, because all the French geologists agree in regarding this zone 
as an essential part of the Cenomanien. On the other hand, we 
eould not exclude the zone of P. asper because it is an essential part 
of our Upper Greensand, and it would be impossible to draw a 
continuous line of division in the midst of a mass of soft sands. 
Hence we are driven to conclude that the only satisfactory solution 
of the difficulty is the introduction of a new name fur the group of 
beds which lie between the Vectian and the horizon known as the 
Chloritic Marl. I have considered all the places situate on the 
Gault and Greensand in the south of England, but have not suc- 
ceeded in finding any town, river, or district, which affords so 
appropriate a name as Devisian. The fact is that the tracts occupied 
by the outcrop of these strata were in British and Roman times 
covered with such thick woods and were so full of springs and 
quagmires that they were unsuited for the establishment of towns or 
military stations and were for the most part wild and uninhabited 
districts like Selwood Forest. From this fact Sylvanian has been 
suggested as a name, but as most other argillaceous outcrops were 
equally sylvanian it is not sufficiently distinctive, and it lacks the 
definite association with a typical district which is embodied in 
Devisian. 
My object in discussing this question has been to make it plain 
that the use of the old names Gault and Upper Greensand only 
serves to perpetuate error; it is not merely a fancy on my part that 
such a name as Devisian or Sylvanian will look prettier and be more 
convenient, but it is absolutely necessary if our names are to signify 
definite portions of geological time that a new name should be found 
for that portion of time during which the Gault and Upper Green-. 
sand were formed. I wish it to be understood that I am not now 
proposing any special name; I have simply discussed the names 
that seem to me to be available, and if any of my readers can suggest 
a better name I shall be very willing to consider its merits, 
