Barber. — Cup ressinoxy Ion vectense . 337 
these comparisons until older specimens presenting the same 
peculiarities have been examined. 
From the frequent occurrence of this type of wood in 
the Lower Greensand of the Isle of Wight, I have decided 
to call it Cupressinoxylon vectense. 
Annual Rings. 
The rings of growth are so peculiar as to deserve an ex- 
tended description. They are compound in all the specimens 
(Fig. 1). They are readily visible to the naked eye, and each 
is seen to consist of a broad, inner, clear, and a narrow, 
outer, denser portion. The former, under a low magnifying 
power, is seen to consist of wide and more or less thin 
walled * spring ’ elements. The latter is, however, not homo- 
geneous, but is composed of a varying number of dark lines 
in a lighter matrix. The dark lines are narrow bands of 
thick-walled, flattened cells, and the lighter parts between 
them consist of wider cells with thinner walls resembling 
the cells of the inner portion of the ring but not so large 
(Fig. 2). 
Under the microscope the dark bands of each series strongly 
resemble the ‘autumn,’ ‘late,’ or better ‘summer’ wood of 
living trees ; but they are seen to vary much in extent 
and thickness, frequently anastomosing with one another or 
fusing together at short distances along the circumference 
of the section. What is one thin band at one place breaks 
up to from two to five in another or increases greatly in 
thickness. Besides these regularly grouped bands of flattened 
cells, other less definite ones may be traced at various points 
in the wide zone of spring tracheides. A close examination 
of this part of the ring shows that there are frequent changes 
in the radial width of the elements and the thickness of their 
walls, sometimes constant for some distance or indeed all 
round the section, at other times limited to a few cells only. 
In the majority of cases the narrow dark bands would be 
classed as ‘ false ’ or ‘ partial ’ rings. They show a gradual 
