Near the village of Caldueñin is a large cave entrance in a cliff, at the head of a dry valley. Water only flows from the cave entrance in exceptionally wet weather, but the main stream of the Arroyo Bolugas is met just inside, in a large chamber. The stream sumps both upstream and down, at least during the weather conditions prevailing while the expedition was there.
At the top of the cliff is a short cave containing some long-dead stalactites, obviously a long abandoned resurgence.
The stream resurges in a most impressive Vauclusian rising just above the village of Cortines. The roof can be felt to rise just inside, and it is possible at it might be feasible to enter in very dry weather.
Downstream is a small resurgence cave, bringing a tributary into the river. After about 20 m the cave becomes too tight for further progress, and it is almost certainly unconnected with the main system.
This cave was shown to us by the village children (with one torch between them). It is at the western end of the saddle between El Mazuco and Caldueñin, and consists of a descending bedding plane. At first it is spacious and well decorated, but eventually it closes down and is blocked by boulders. It might repay digging.