Not oncoliths but rodoliths!

Thanks to Professor Paul Wright I've now identified the round balls we found in Messinian sediments at Cala Cuerva in Almeria as rodoliths - balls created by red algae as it rolls back and forth - see the Wikipedia entry

From the top - close up of a rodolith






The exposure on the south side of Cala Cuerva

The rodolith bed

Rocks in between the birds

Had a great morning in the Sierra de Loja with Mick (see his Loja Wildlife blog for the birdy bits which he does much better than I can) - we saw birds we had never seen before, and really benefited from his expertise.

However, in between times we saw a few rocks as well - the whole area is superb karst - this part of southern Spain is one of the largest around the Mediterranean.
I actually like the windmills by the way and the birds all seem well able to avoid them.
We found some superb acicular calcite crystals of which, since they weren't in situ, we had no compunction about taking examples home. It actually looked as though they might have been brought in with the stone for the graded track we were driving on.

Coming back down the track there are some superb views towards the west. The town of Loja, north of the sierra, lies in a trough between the mountains along the line of the seismically active Crevillente (or Cadiz-Alicante) Fault which runs ENE-WSW just north of the internal zone of the Betic Cordillera and we are looking along the line of this towards Antequera.

Although at the higher levels the beds of limestone are dipping, we didn't see and fold however down towards the bottom of the track, above the A92 and a little way west of the Abades service area is a quarry where the limestone is folded into quite small scale upright folds.

In the face at the quarry's western end there is further evidence of the karstic nature of the area with a section through a vertical pipe lined with flowstone.