Cadastral area: Straník
Area of the natural monument: 0,0357 ha
Protective zone: 0,4503 ha
Date of the proclamation: 1.10.1997
Charakterization:
Important geological locality - exposure with torus lavas of tephra volcanic
association.
Protective motive is geological. It concerns the conservation of the locality of one of kinds
of undersea volcanic activity in the period of lower chalk.
There originated so-called "picrit almond-stone".


Stopping Nr. 13 - Natural monument
Torus lavas by Straník, nature trail of Palacký
(elevation above sea level 416 m)


With Skalka pod kapličkou we introduce to you last selection from the forms of undersea volcanic activity in the lower chalk. Torus lavas of lower-chalk of tephra association of Silesian unity are uncovered here. They are built up by "rounded" fragments of lavas of so-called olivine diabase to diabase picrit.

The edges of the blocks, that build so-called limburgits, falls into the pea-shaped pieces. Separate blocks are filled in with younger lava with tuffitical material (volcanic sand and dust). This lava is often broken down by secondary processes and is considerably carbonized (saturated with calcium carbonate).

Torus lavas originate by undersea eruptions on the steep inclines, when the lava flowing on the incline gets torn into pieces, that gather then on the foot of a slope.

Rockery is unique natural formation on the area of the Czech republic. According to the natural and landscape laws the whole formation is protected as a natural monument.

In the past by building of two-flight staircase to the chapel on the peak of rockery it so happened that the edges of blocks (loaves) were cut off.