Formation of high-level cloud with fish bone arrangement hence the subspecies vertebratus. Ci vertebratus tend to form where the air at high altititude is moist enough combined with the presence of wind shear whereby the descending part of the rotating air is clear whereas the thin cloud part form where the air is rising within this cloud structure. In fact, the meteogram attached herewith had confirmed this whereby the cloud base was at around 300mb or around 9km above sea-level under the presence of wind shear. The distrail on both sets of cloud could have been caused by a passing aeroplane which would have evaporated parts of the cloud.