Lardies (1988) including over 500 specimens from the sections of Ricla, Tosos, Moneva and Penisquera, and Melendez et al.

It is well developed in the NW sector (Veruela-Ricla to Tosos) under black to grey marl and mudstone facies, showing a higher content in siliciclastics in the Northwest (30 to 35 m thickness) and becoming slightly bioclastic in the Tosos-Aguilon area (5 m thickness).

Gracilis Biozone: It is well developed in the NW sector (Veruela-Ricla to Tosos) under black to grey marl and mudstone facies, showing a higher content in siliciclastics in the Northwest where terrigenous input was higher (c.

Attention should be paid to the fossil content in the iron-ooid interval (level 81 of Tosos; levels 106-107 of Aguilon) at the top of the Callovian succession in this locality (the so-called Arroyofrio Bed).

1b, differences in facies and thickness development between Callovian succession in both localities allow inferring a more important terrigenous input in the NW Veruela-Ricla and Tosos Area (Fig.9).