HICK : OUR KNOWLEDGE OF THE YORKSHIRE CALAMITY. 
5 
be published until we are in possession of longitudinal sections, with- 
out which the story told would be still incomplete, and on some 
points might even be misleading. 
The Leaves. 
The leaves of Calamitw, as found in casts and impressions are 
mentioned by various Palaeophytologists. Carruthers" describes them 
as " linear-acuminate," each whorl containing " from ten to twenty 
leaves." Renaultf says, "leurs feuilles sont verticillees, libres, 
ou tres faiblement soudees a la base, lineaires-lanceolees." SchenkJ 
describes the leaves of Calamitina varians Weiss, as having well- 
preserved leaves, which are linear aud lanceolate at the apex, with a 
distinctly contrasted, ovate, thickened basal part, traversed by a 
furrow. Solms-Laubach|| tells us that " the leaves of Calamitw are 
unusually rare," and that " they are linear and not united laterally 
into a sheath." But I have nowhere found any definite statements 
regarding the leaves of our Yorkshire type, Artlwopitys, nor any 
information on the internal structure of leaves that have been found 
attached to the stems of other forms. 1 conclude therefore that on 
these points little or nothing is known. 
Reproductive Structures. 
Numerous accounts have been published, often accompanied by 
figures, of several kinds of spikes or Strobili which are regarded by 
their describers as the fruit of Catamites. One of these has been 
described by Williamson § as the l< true fructification of Calamites," 
and as the only one which at present is entitled to be so regarded. 
According to his description the fruit has an axis which repeats the 
structure of a Calamitean twig of the Arthropitys type, and from 
which, at intervals, nodal disks are given off which bear a number of 
free bracts at the margin. From the upper surface of each nodal disk 
sporangiophores arise which bear sporangia, but how the latter are 
attached he has not yet been able to discover. 
* On the Structure and Affinities of Lepidodendron and Calamites. 
t Structure Comparee de quelques tiges de la Flore Carbonifere, p. 218. 
X Die fossilen Pflanzenreste, p. 124. 
|| Fossil Botany : Eng. ed., p. 295. 
§ Philosophical Transactions, 1888. 
