It is a simple building located at the top of Sant Marc mountain and overlooking the Bastereny valley, the Lillet valley, Gavarrós and part of the Coma valley. It has a rather rectangular plan with an east-west orientation and without having a defined header. The door is open at noon and does not present any kind of lighting opening except for a small hole in the west facade. The construction equipment is made of poorly worked and squared stone blocks, joined with lime mortar and arranged in rather irregular rows with well-defined corners. The south-facing doorway is surmounted by a stone lintel. Through old photographs we know that it was covered with a barrel vault and that the roof was made of licorella slabs. The pavement is made of stone slabs.
Observations:
From this church comes the tradition that on the Vigila de Sant Marc the farmers of Brocà walked up there and lit a big bonfire that could be seen from the whole Bastereny valley. The following day the gathering was held with a mass and the distribution of bread. This tradition that Joan Serra i Vilaró in his book of the Baronies of Pinós and Mataplana mentions to us that there were a total of 15 farms in Brocà and that the people of Bagà went up there in procession. Today this tradition is still alive and despite the gathering and distribution of the bread taking place in Sant Martí de Brocà, the day before still goes up to Sant Marc to light the bonfire and make ressopó.
According to Mr. Serra i Vilaró in his book of the baronies of Pinós and Mataplana, research in his archives, in book III and extracted from the original documents of the ACA. Notaries Bagà mentions that the first documentary reference is from 1320 and in 1370 it is given to the hermit Bernat Capdevila. Later and in a document from 1439 he mentioned that they bequeathed a quarter of oil to Sant marc de Paller, interpreting that it belonged to this church. In 1933 the church had no worship and the image was moved to Sant Genís de Gavarrós. The image published in the Gavin archive in 1967 shows the chapel still with the covering and roof standing