Oeolocjical Society. 295 



Oolit'i*. Trunks, pith-casts, etc. Much I and Marj'land. 



foliag-e of various types. Wil- I C.jenneyana, 



liamsonia gigas and other fruit- I C'- ingens, 



impressions. J C. xrielandi, etc. 



W. scotica. 



Williamsoniella coronata. "] Rich impressions in 



Lias. Foliage and WiUiamsonia \ Mexico of TFiiJiam- 



fraits (India). ( IT ^^ "^^""^ 



J roiiagfe genera. 



■^^^^'*''^- Wielandiella nmjnstlfolia and foliage. 



The group is by far the most characteristic of all the plants of 

 the Jumssic and Lower Cretaceous, during which periods its 

 distribution was almost world-wide. It was locally, if not univer- 

 sally, dominant, and was the most highly evolved" plant-group of 

 the epoch oi which we are cognizant. 



Three chief points of interest are to be noted in the geoloo-ical 

 distribution of these plants: {a) that the most numerous hi 'hly- 

 speciahzed trunks reach their maximum in the Jurassic and Lower 

 ( i-etaceous Periods, when their distribution was practically world- 

 wide; (J) that the oldest and therefore presumably the most 

 primitive t3rpe, Wielandiella, is externally less like the living cycads 

 than the commoner later forms, while these latter are utterly unlike 

 the living genera in their fructifications ; {c) that the geologically 

 youngest cone is the largest yet discovered, occurring in the Gault 

 when the extinction of the group appears already to have set in 



Lontraiy to what might have been anticipated from their 

 external likeness to the living Cycads, coupled with their great 

 geological age, the fossil ' Cycads ' are much more complex and on 

 a higher level of evolution than the living group. • It seems to the 

 Author to be extremely unlikely that the fossil and the livino- forms 

 have any direct phylogenetic connexion nearer than a remote 

 unknown, common ancestor. The mooted connexion between the' 

 fossil Cycads and the Angiosperms is highly suggestive, but lacks 

 data tor its establishment. 



A short discussion followed, and the thanks of the Fellows 

 present were accorded to Dr. Stopes for her lecture. 



January 10th, 1917— Dr. Alfred Harker, F.R.S., rresident, 

 ill the Chair. 



The following communication was read : 



'Balston E.xpedition to Peru: R.port on Graptolites collected 



The specimens of graptolites were collected from the rocks of 

 the Tnamban district in Peru ])y Capt. Douglas, under whose name 



