LES: REPORTS ON THE STATE OF SCIENCE. 
Tables drawn up by Dr. Vaughan to exhibit the Present State of 
Knowledge of the Avonian in the British Isles. 
Table I. exhibits the zones and sub-zones of the Avonian, and the 
corals which characterise and diagnose them. 
In Table II. I have attempted to assign to the several phasal develop- 
ments their correct position on the Avonian scale. 
Table III. gives the zonal sequence at several points in the British 
Isles. In almost all cases I have seen the material on which these correla- 
tions are founded, and my thanks are tendered most heartily to those 
workers who have allowed me to present the information contained in this 
table before its actual publication elsewhere. 
TABLE I, 
The Avonian ZonEs and SUBZONES and the Corals that characterise them. 
THE ZONES. 
Dibunophyllum Zone (D). 
Dibunophyllum enters and attains a maximum. 
Lithostrotion junceum enters and is common throughout. 
Seminula Zone (S). 
Lithostrotion enters and is continuously abundant. 
Carcinophyllum enters and is not uncommon, 
[Maximum of Seminula ficoides.] 
VISEAN. 
Syringothyris and Caninia Zone (C), 
Giganteid Canini@ enter and attain a maximum. 
Michelinia grandis enters and attains a maximum. 
[The maximum of very large Syringothyris. | 
Zaphrentis Zone (Z). 
Simple Zaphrentes (of non-Caninoid and of non-Densiphylloid types) enter and 
attain a maximum. 
Michelinia favosa attains a maximum at extinction, 
TOURNAISIAN 
Cleistopora Zone (K). 
OCleistopora occurs throughout, but is common at only a few levels. 
