34 phoceedings of the 



of some Trigonocarpons contained in tliem '' (L^oS), is a valuable 

 contribution, from two points of view. An excellent account of the 

 nature and occurrence of the calcareous nodules (coal-balls) is 

 given, the earliest, I believe, extant, but this was presumably the 

 work of Binney. The writers notice the absence of fern-fronds- 

 from their petrified material, saying : " It is difficult to conceive the 

 delicate fronds of Ferns so preserved that their structure should be 

 recognized on a transverse section of them in the fossil state." Of 

 course the structure of the leaves of some of the Pteridosperms- 

 tthen included under Ferns) is now well known, but the rarity of 

 true fern-fronds in the petrified condition is remarkable, considering 

 (he frequency of their petioles and stems. 



As regards the Trigonocarpons, the writers proved that the 

 common nut-like specimens are merely casts of tlie seed-cavity. 

 They give, from their structural specimens, an excellent descrijition 

 of the " outer and second integument " (our sarcotesta or outer 

 fleshy layer, and sclerotesta) ; the nuccllus with its vascular 

 bundles is also described, but not the outer system of bundles in 

 the sarcotesta. 



They made a detailed comparison with the seed of SaJisbtiria 

 (GfinJcffo), and believed the affinities of I'r'ir/onorarpon to be Coni- 

 ferous rather than Cycadaceous. As a matter of fact, Brongniart'a 

 suggestion of Cycadaceous relationship now seems nearer the truth. 

 The authors say that association gives no clue — they were not 

 then acquainted witli the Aletliopttris-\eix\G^ whicb so generally 

 accompany these seeds. 



They had some suspicion that 2'rir/onocarjwn might belong to 

 Sigillaria, a suggestion Avhich perhaps shows that Brongniart's 

 belief in the Gymnospermous nature of Shjillaria was beginning to 

 have an undue influence. The paper is an important one, as it 

 placed our knowledge of one Palaeozoic seed, at least, on a scientific 

 basis. 



Tavo papers by Hooker relate to the problematic organism 

 Pachytheca, of Silurian age. The earlier work is "On the Spheroidal 

 Bodies, resembling Seeds, from the Ludlow Bone Bed " (1852). 

 The outer zone of the spheroidal thallus consists of radiating cells, 

 and in this first paper Hooker said : " This simple structure of spore- 

 sac is very characteristic of the natural order Lycopodiaceae." He 

 was thinking, no doubt, of the well-known columnar layer which 

 forms the outer wall of the sporangium in Lepidostrohus. On a 

 re-examination of specimens in 1875, he gave up this tentative 

 hypothesis and recognised the Algal nature of the organism. His- 

 latest contribution to fossil Botan)' is a short paper on PachijtJieca, 

 published 37 years later in the ' Annals of Botany ' for 1889, 

 illustrated by beautiful drawings from his own hand, showing the 

 detailed structure. He points out the remarkable density and 

 power of resistance to deformation that the thallus must have 

 possessed, and discusses the question whether the internal filaments 

 might be parasitic. He cites the opinions of other botanists, but 



